High Court dismisses planning appeal regarding Leisler's Bat roost error due to lack of material impact on outcome.

[2025] IEHC 158

THE HIGH COURT

PLANNING & ENVIRONMENT

[H.JR.2024.0000708]

IN THE MATTER OF SECTION 50 OF THE PLANNING AND DEVELOPMENT ACT 2000 (AS

AMENDED) AND SECTION 15 OF THE CLIMATE ACTION AND LOW CARBON DEVELOPMENT

ACT 2015 (AS AMENDED)

BETWEEN

COLIN DOYLE, FRIENDS OF THE IRISH ENVIRONMENT CLG,

FUTUREPROOF CLARE, MARTIN KNOX AND CHRISTINE SHARP

APPLICANTS

AND

AN BORD PLEANÁLA, THE GOVERNMENT OF IRELAND, IRELAND AND THE ATTORNEY

GENERAL

RESPONDENTS

AND

ART DATA CENTRES LIMITED

NOTICE PARTY

JUDGMENT of Humphreys J. delivered on Friday the 21st day of March 2025

1. The Bat in Building 6C could be an episode title in a Scandi Noir series. But it describes our

subject here. This judgment concerns a single roost containing a single Leisler’s Bat, who as of

March 2022 was a resident in a crack in the external wall of a structure with the forbidding, if not

slightly Soviet, name of Building 6C, a barn shed in farmland near Ennis, Co. Clare. The species is

named for Dr Johann Philipp Achilles Leisler (b. 1771/72) of Hanau in Germany, who in 1813

proposed the introduction of legal protection of insectivorous bats. He has been described as the

father of legal bat protection in Europe, although his efforts took some time to reach fruition. The

first law in that regard was enacted in Hungary in 1901, followed by Salzburg in 1909, Finland in

1923, Denmark in 1931, Liechtenstein and Prussia in 1933, Portugal in 1934, Germany more widely

in 1936, Austria overall in 1939, Italy in 1939, Yugoslavia in 1947, Poland in 1952, the USSR in

1960, Bulgaria in 1962, Czechoslovakia in 1965, Switzerland in 1967 and Sweden in 1968. Ireland,

not uncharacteristically in environmental matters, brings up the rear in 1976, a mere 200 years after

Leisler’s birth. (See Gustav Kirk, “Gesetzlicher Fledermausschutz in Europa”, Decheniana-Beihefte

Nr. 18, Seite 45—50 Bonn, Oktober 1971)

(https://www.zobodat.at/biografien/Leisler_Johann_Philipp_Achilles_Decheniana_BH_18_0045-

0050.pdf).

Geographical context

2. Two related board decisions are challenged here. The data centre decision

(https://www.pleanala.ie/en-ie/case/314474), involves the construction of six two-storey data

centre buildings, associated structures and all ancillary site works on a 60 hectare site at Tooreen,

Cahernalough and adjacent townlands, Tulla Road, Ennis, Co. Clare, subject to conditions for a 10-

year period at Tooreen, Cahernalough, Knockanean, Ballymacahill, Muckinish and Rosslevan, Tulla

Road, Ennis, Co. Clare

3. The substation decision (https://www.pleanala.ie/en-ie/case/313895) involves the

development of a 110kV GIS substation with two 110kV underground transmission cables connecting

to existing 110kV overhead lines to the north, and two 110kV underground cables connecting to the

existing Ennis 110kV substation and associated works in the Townlands of Tooreen, Cahernalough,

Knockanean, Ballymacahill, Muckinish and Rosslevan to the north-east of Ennis, on the Tulla Road

(R352), Co. Clare.

4. The inspector takes up the detail (section 1.0):

“The appeal site is located within the townlands of Toureen and Cahernalough, c.4km to the

NE of Ennis in County Clare. The rural site is located on the northside of the Tulla Road

(R352) and the site and surrounding area is characterised by agricultural uses. There are

several dispersed houses and farm buildings in the vicinity and the lands form part of a

larger area that has been designated for future development.

The site is located to the E of the M18 motorway and the Junction 13 slip road, N of the

R352 (Tulla Road) and S of the L4608 local road at Cahernalough and Ballymacahill. It is

bound to the N and E by agricultural land, to the W and NW by the Spancelhill Stream, and

to the S by the Tulla Road. There are several dwelling houses and farm buildings located

within and to the N of the site, and to the S along the Tulla Road, and there is a small

residential area located on the westside of the M18. The Ennis 110kV substation is located

to the W of the site and the M18 slip road, the site is traversed by several overhead electrical

cables and the lands in the E section of the site are traversed by a gas pipeline along a N-S

axis. The main vehicular access to the site is off the R352 (Tulla Road) in the E section of

the site.

The overall c.60 ha moderately elevated site (data centre & substation) mainly slopes up

gently from SW to NE. The site and field boundaries are defined by mature hedgerows,

trees and stone walls, and there are pockets of woodland around the perimeter of the site

and within the W and SW sections. There are several ponds within and adjacent to the site,

including Toureen Lough (SW) and Ardnamurry Lough (NE). The lands mainly drain in a SW

direction via surface and groundwater towards the Ballymacahill / Spancelhill Stream, which

flows between 2 x attenuation ponds associated with the M18 motorway, before joining the

Gaurus River to discharge S to the River Fergus and ultimately the River Shannon.”

Facts in relation to the application

5. On 16th July 2021, the notice party submitted a planning application to Clare County Council

(the council) for a development comprising the construction of six two-storey data centre buildings,

associated structures and all ancillary site works on a 60 hectare site at Tooreen, Cahernalough and

adjacent townlands, Tulla Road, Ennis, Co. Clare (Planning Reg. Ref. No. 21/757) (the data centre

application). The data centre application was accompanied by, inter alia, an environmental impact

assessment report (EIAR) and a Natura Impact Statement (NIS).

6. On 8th September 2021, the council sought further information in relation to the data centre

application (the RFI) and a response to the RFI was provided on behalf of the notice party on 25th

February 2022. The RFI response was readvertised as required by the council on the basis that it

contained significant additional data.

7. Clarification on the RFI response was sought by the council on 28th April 2022, and a reply

was submitted on 10th June 2022, which included an updated EIAR (described in the board’s order

as a “consolidated EIAR”). The clarification response was readvertised as required by the council on

the basis that it contained significant additional data.

8. On 8th August 2022, the council made a decision to grant planning permission, which

decision was the subject of a number of third-party appeals to the board, including by the applicants.

9. Relatedly, on 23rd June 2022, the notice party submitted a strategic infrastructure

development (SID) application to the board under s. 182A of the Planning and Development Act

2000 (as amended) (the 2000 Act) for the development 110kV GIS substation with two 110kV

underground transmission cables connecting to existing 110kV overhead lines to the north, and two

110kV underground cables connecting to existing Ennis 110kV substation to the west and associated

works (the substation application).

10. On 11th December 2023, an inspector appointed by the board to prepare a report in respect

of the data centre appeals, submitted a report to the board, which contained a recommendation that

planning permission should be granted, subject to 17 conditions. The inspector also conducted an

environmental impact assessment (EIA) and an appropriate assessment (AA).

11. The same inspector was also appointed by the board to prepare a report on the substation

application and on the same date, she submitted a report to the board on that application, in which

she recommended that planning permission be granted, subject to 14 conditions.

12. A board direction dated 27th March 2024, in respect of the data centre application, indicated

that the board decided to grant permission generally in accordance with the inspector’s

recommendation. The board direction indicated that the board had undertaken an AA in respect of

a number of “screened in” European sites. The direction indicated that the board considered that

the information before it was sufficient to undertake a complete assessment of all aspects of the

proposed development in relation to the conservation objectives of the said European sites using the

best available scientific knowledge in the field.

13. The board’s direction also indicated that the board undertook an EIA of the proposed

development.

14. A board direction dated 27th March 2024, in respect of the substation application is framed

in similar terms to that relating to the data centre application.

15. On 5th April 2024, the board granted planning permission for the data centre development,

subject to 17 conditions. On the same date, it granted permission for the substation development,

subject to 14 conditions. The board’s orders, in respect of both, records that it carried out an EIA

and an AA of the proposed development.

Procedural history

16. On 30th May 2024, the applicants’ statement of grounds was filed in the Central Office.

17. On 26th June 2024, I granted the applicants leave to apply for judicial review seeking, inter

alia, an order quashing the board’s decisions taken on 5th April 2024. On the same date, I fixed a

hearing date of 25th February 2025 for the judicial review, as a two-day case.

18. On 7th October 2024, in advance of delivering a statement of opposition, the board’s

solicitors wrote to the other parties indicating that the board had decided not to oppose the

applicants’ claim for certiorari quashing the board’s decisions on the data centre application and the

substation application. Their letter stated:

“Having regard to the circumstances of this case and, in particular, the plea(s) advanced at

Core Ground 6 of the said Statement of Grounds – namely, that the Board erred in law in

failing to consider adequately the environmental effects of the proposed developments on

the environment, specifically in terms of impacts on bat fauna for the purposes of the

Environmental Impact Assessment carried out by the Board”.

19. On 25th November 2024, the notice party communicated to the court that it was seeking

that the hearing date of 25th February 2024 would be retained to facilitate a hearing in relation to

core ground 6 only (as it turned out, only in respect of part of that core ground), as the notice party

intended to resist certiorari being granted by reference to the ground on which the board’s

concession was made. I directed that the matter proceed as a modular hearing for one day on 25th

February 2025, on the question of whether the court should quash the decisions in light of the

board’s concession.

20. On 5th December 2024, the notice party’s solicitors wrote to the board’s solicitors stating:

“We note that there are sixteen paragraphs contained in the Applicant's Statement of

Grounds with respect to Core Ground 6. Can you please confirm the exact point(s) pleaded,

under Core Ground 6, which forms the basis of your client's concession, so that the precise

contours of the upcoming hearing can be defined”.

21. On 9th December 2024, the board’s solicitors wrote to the solicitors for the other parties,

clarifying that:

“The Board accepts the errors pleaded in the particulars set out at §91-§93 of the Statement

of Grounds insofar as same are premised on the Inspector’s statement (at pg.74 of the

Inspector’s Report) … On the basis that the information before the Board, including the

updated EIAR, the evidence demonstrated that the Proposed Development would result in

the loss of a bat roost. Thus, in failing to recognise the loss of the bat roost, it is conceded

that the Inspector and the Board erred in failing to identify, consider and assess the potential

impacts of the Proposed Development on bat fauna for the purposes of EIA.”

22. On 16th December 2024, I directed that the hearing scheduled for 25th February 2025 would

be in relation to the matters in §§91-93 only of the applicants’ statement of grounds, following that

clarification from the board.

23. On 23rd December 2024, the notice party served a limited statement of opposition, together

with a verifying affidavit sworn by Ms Deborah Delaney and an affidavit of Mr Colm Clarke. The

statement of opposition addressed the relevant sub-grounds but also referred to other contextual

matters such as tree surveys which were touched on in other pleaded sub-grounds.

24. On 23rd January 2025, the applicants’ solicitors sent a letter to the notice party’s solicitors

asserting that the notice party’s statement of opposition addressed the entirety of the grounds

pleaded in relation to core ground 6. The letter stated that:

“This was not what was required and would appear to be an attempt to impermissibly expand

on the matters directed to be heard at the hearing. The Affidavit of Ms Delaney traverses

matters far beyond those in ground 91- 93 of the Statement of Opposition. Furthermore,

your client has delivered an affidavit of Colm Clarke ecologist and it is clear that this Affidavit

also addresses issues which go far beyond what is in issue in relation to grounds 91-93 of

the Statement of Opposition.”

25. The letter indicated that the applicants would apply to have parts of the statement of

opposition struck out and the notice party’s affidavits “resworn to address the matters relevant to

those to be addressed at the forthcoming hearing”.

26. On 24th January 2025, the notice party’s solicitors sent a letter to the applicants’ solicitors

stating:

“Our client fully accepts that the issue which the Court has to decide on 25 February 2025

relates specifically to paragraphs 91-93 of the Statement of Grounds, concerning the effect

of a factual error which appears on page 74 of the Inspector’s report on the Data Centra

application, in the section of her report dealing with ecology issues and bats in particular.

The extract states, inter alia, that ‘[t]he various EIAR desk-top and site surveys confirm that

the site and environs are frequented by bats, and although some of the older farm buildings

may also have roosting potential, the applicant confirmed that no roosts were recorded

during the surveys …’

It would be entirely unrealistic and artificial, and a waste of court time, to ask the Court to

determine whether the Inspector’s factual error should result in the Board’s decision being

quashed without addressing the other matters [in Core Ground 6], including the allegation

that the Board had no objective information before it in terms of the impacts on bat fauna

for the purposes of the EIA and/or the issue of whether a derogation licence was required in

advance of the Board’s decision. Indeed, were our client to simply deal with the issue of the

Inspector’s factual error in isolation from the treatment of the issue of bat fauna generally,

it could expect to be criticised by both your client and the Court, given the overlap between

the issues and the critical requirement of the Court to have an understanding of the totality

of the matters raised in Core Ground 6 in considering proportionality. Furthermore, given

that our client is asking the Court to exercise its discretion against quashing, it is imperative

that the Court has a full picture of the issues in order to properly consider the matter. In so

doing, our client is not asking the Court to do anything other than determine the issue with

respect to the Inspector’s factual error.”

27. On 27th January 2025, on the application of the applicants, the matter was listed before the

court where I clarified – ultimately with the agreement of both parties participating in this module –

that where the board concedes a ground and the court conducts a modular hearing on the notice

party’s application determining whether the decision should be quashed in light of the board’s

concession, for the purposes of determining that issue, the court must approach the application on

the basis that all other issues would be resolved in the notice party’s favour. However, in the event

that the complaint fails under this heading as a basis for certiorari and the matter proceeds to a

further module dealing with the remaining grounds which the board has not conceded, those other

issues revert to being fully in contest for the purposes of the subsequent module.

28. On 3rd February 2025, the applicants’ solicitors confirmed that the applicants would not be

filing replying affidavits in response to the notice party’s limited statement of opposition and

affidavits.

29. On 5th February 2025, the notice party delivered its legal submissions.

30. On 19th February 2025, the applicants delivered their legal submissions.

31. The module was heard on the basis of the expedited procedure on 25th February 2025, and

judgment was reserved on that date.

The effect of modularisation

32. One notable procedural skirmish that developed during the hearing was a fall-out from the

issue just referred to. The question was as to the effect of the order for modularisation of sub-

grounds 91-93 as Module I in respect of the argument that there was no prior derogation licence.

It’s true that the notice party did mention this in correspondence, as noted above, but this wasn’t

particularly pursued in advance as an issue to form part of this module, if for no other reason than

the fact that the central plea of lack of a prior licence arises in later sub-grounds and not in sub-

grounds 91-93. The effect of the modularisation order was that the board and the State absented

themselves from Module I and the issue proceeded as between the applicants and the developer.

The idea was that if the developer won the present issue, there would be a Module II on all other

issues. The skirmish was about whether the applicants could now advance sub-grounds 91-93 by

reference to the lack of a derogation licence which is an issue pleaded in sub-grounds 96-101.

33. As noted above, the whole basis of modularisation is that one has to proceed on the

assumption that the other grounds don’t add anything – that the decision is valid on all grounds

other than the ones to which the module relates. Another example – in the case of modularising

domestic points, it is to be assumed that EU law doesn’t add anything. That is only an assumption

which is revisited if the challenging party loses the module and if we therefore have to move on to

the next module.

34. Applying that here, the upshot is that the present module has to proceed on the assumption

that the lack of a prior derogation licence did not give rise to illegality. That has the effect that the

applicants can’t argue, in the present module, that the inspector’s error is material because of an

issue pleaded in sub-grounds falling outside the module. But it doesn’t have the effect that the

applicants can’t make that argument at all. The logical outcome (which the developer did, after

discussion, accept) is that if we get to a Module II, the applicants can at that stage argue that the

error is material due to the lack of a derogation licence (although what this adds, or in other words

how they can win on that issue but lose on the substantive issue of the lack of a licence, isn’t at all

obvious at first sight).

35. Furthermore, attempting to deal with the derogation licence issue now would be procedurally

inappropriate in the absence of potentially interested parties, the board and the State. So that was

a non-starter in any event.

36. Of course the applicants’ misconceived attempt to go beyond sub-grounds 91-93 in this

module is somewhat ironical placed in the context of their strident and equally misconceived

attempts to condemn the developer for allegedly going beyond those sub-grounds by referring to

issues regarding trees, as referenced above. But we don’t need to get into that further at this stage.

Relief sought

37. The reliefs sought in the statement of grounds are as follows:

“1) An Order of Certiorari quashing the decisions, and each of them, dated 5 April 2024

of the first named Respondent granting planning permission to the Notice Party for:

(a) the construction of a proposed data centre (PDC) located in Ennis, County Clare,

comprising six two-storey data centre buildings with three storey plant/office levels and

associated ancillary development that will have a combined gross floor area of 118,740

square metres, including a 120MW gas powered electricity generation facility and

dispatchable electricity generation facility powered by 66 diesel generators (ABP-314474-

22, ‘the Data Centre Decision’);

(b) the provision of a new 110 kilovolt (kV) Gas Insulated Switchgear (GIS) grid substation

(the Substation), two 110 kV underground transmission cables connecting to existing 110kV

overhead lines to the north of the proposed substation, and two 110kV underground

transmission cables connecting to the existing Ennis 110kV grid substation (located to the

east of the M18 and to the north of the Tulla Road (R352), along with associated and ancillary

works) (ABP-313895-22, ‘the Substation Decision’).

[In this Statement of Grounds any reference to a document contained in the planning files

before the Board or the Planning Authority relate to the application and appeal in respect of

the PDC, unless otherwise stated].

2) Such declaration(s) of the legal rights and/or legal position of the applicants and (if

and insofar as legally permissible and appropriate) persons similarly situated and/or of the

legal duties and/or legal position of the respondents as the court considers appropriate.

3) A declaration that the State’s adoption of the ‘Government Statement on the Role of

Data Centres in Ireland's Enterprise Strategy July 2022’ is invalid as it was not subject to

assessment for the purposes of Articles 1 and 3 of Directive 2001/42/EC of the European

Parliament and of the Council of 27 June 2001 on the assessment of the effects of certain

plans and programmes on the environment.

4) If necessary, a stay on works being carried out pursuant to the Data Centre Decision

and the Substation Decision pending the resolution of these proceedings.

5) A Declaration that the within proceedings are covered by the protective costs

provisions of Section 50B of the Planning and Development Act 2000 (as amended), and/or

otherwise.

6) Further or other orders.

7) Costs.”

Grounds of challenge

38. The core grounds of challenge are as follows:

“DOMESTIC LAW GROUNDS

1. The Data Centre Decision is invalid in that the Board failed to apply and/or consider

its mandatory obligation under section 15 of the Climate Action and Low Carbon

Development Act 2015 (as amended by Section 17 of the Climate Action and Low Carbon

Development (Amendment) Act 2021), namely in so far as practicable, to perform its

functions in a manner consistent with the matters stated in section 15, including (a) the

most recent approved climate action plan, (the Climate Action Plan 2023), (d) the

furtherance of the national climate objective, and (e) the objective of mitigating greenhouse

gas emissions (GHG emissions) and adapting to the effects of climate change in the State;

and/or failed to provide sufficient reasons to explain how it sought to apply and/or consider

its mandatory obligation under the 2015 Act, further particulars of which are contained

below.

2. The Data Centre Decision is invalid in that the Board acted irrationally, erred in law

and/or failed to provide reasons and/or adequate reasons, in finding that the PDC would

have potentially positive environmental impacts, based on a future switch to the use of

sustainable/renewable gas supplies, which do not exist in sufficient volumes for any practical

application in respect of the PDC and which are not expected to exist in sufficient volumes

for any practical application in respect of the PDC at any point during the operational phase

of the PDC, further particulars of which are contained below.

3. The Data Centre Decision is invalid in that the Board acted irrationally by failing to

require any mitigation of the GHG emissions from the PDC, further particulars of which are

contained below.

EUROPEAN LAW GROUNDS

4. The Data Centre Decision is invalid in that the Board treated the Government

Statement on the Role of Data Centres in Ireland's Enterprise Strategy July 2022 as the

framework for development consent in respect of data centres; while simultaneously

deciding that the Government Statement on the Role of Data Centres in Ireland's Enterprise

Strategy July 2022 is not a plan or programme to which Article 3(2) of the Strategic

Environmental Assessment (SEA) Directive applies, further particulars of which are

contained below.

5. The Data Centre Decision is invalid as it relied on the Government Statement on the

Role of Data Centres in Ireland's Enterprise Strategy July 2022 which is invalid as it was not

assessed for the purposes of Articles 1 and 3 of Directive 2001/42/EC of the European

Parliament and of the Council of 27 June 2001 on the assessment of the effects of certain

plans and programmes on the environment, further particulars of which are contained below.

6. The Data Centre Decision and the Substation Decision are invalid as the Board failed

to consider adequately or at all the environmental effects of the proposed development on

the environment in terms of impacts on bat fauna for the purposes of the EIA assessment

carried out by the Board and/or had no objective information before it to support a conclusion

of no significant effects on the environment for the purposes of the Board’s EIA assessment

and/or impermissibly granted development consent prior to a decision granting a derogation

licence authorising bat roost removals and/or disturbance to bat species, further particulars

of which are contained below.

7. The Data Centre Decision is invalid as the Board granted planning permission in

breach of Article 4(1) of Directive 2000/60/EC of the European Parliament and of the Council

of 23 October 2000 establishing a framework for Community action in the field of water

policy (the ‘Water Framework Directive’) and/or Regulations 4 and 5 of the European

Communities Environmental Objectives (Surface Waters) Regulations 2009 because the

Board did not ensure that the grant of planning permission would not cause a deterioration

of the status of a body of surface water or that it would not jeopardise the attainment of

good surface water status or of good ecological potential and good surface water chemical

status and/or the Board could not have arrived at that conclusion in the absence of the

developer making available to the public during the procedure for approving the project the

data which were necessary in order to assess the effects of the development on receiving

waterbodies, further particulars of which are contained below.

VALIDITY GROUND

8. The State’s adoption of the Government Statement on the Role of Data Centres in

Ireland's Enterprise Strategy July 2022 is invalid as it was not subject to assessment for the

purposes of Articles 1 and 3 of Directive 2001/42/EC of the European Parliament and of the

Council of 27 June 2001 on the assessment of the effects of certain plans and programmes

on the environment, further particulars of which are contained below.”

Pleas regarding the error in the inspector’s report

39. The relevant ground for present purposes is core ground 6:

“6. The Data Centre Decision and the Substation Decision are invalid as the Board failed

to consider adequately or at all the environmental effects of the proposed development on

the environment in terms of impacts on bat fauna for the purposes of the EIA assessment

carried out by the Board and/or had no objective information before it to support a conclusion

of no significant effects on the environment for the purposes of the Board’s EIA assessment

and/or impermissibly granted development consent prior to a decision granting a derogation

licence authorising bat roost removals and/or disturbance to bat species, further particulars

of which are contained below.”

40. As noted above, we are not dealing with the totality of that ground now, just one issue in

sub-grounds 91 to 93. Sub-grounds 86 to 90 set out necessary context:

“86) By way of further particulars of the claim, the revised Environmental Impact

Assessment Report submitted by the Developer in June 2022, in respect of both the PDC

and the Substation identified very significant impacts on bats. The trees and hedgerows

within the site were identified as significant commuting and foraging pathways for bats. Tree

surveys identified a total of 17 trees with roost potential, albeit roost emergence/re-entry

surveys on trees were not carried out (EIAR Chapter 7 p.69). Figure 7.23 which was

supposed to show the location of these trees is missing from the EIAR. A number of the

farm buildings on the site were identified as either containing roosts or having roost

potential. Residential buildings were assessed externally but not internally owing to

concerns over Covid 19. At Table 7.9 of the EIAR the suitability of the buildings for bat

roosts was identified, including a number of confirmed bat roosts on site. It noted, in the

revised EIAR, that an additional roost was identified in Barn 6C in March 2022 bringing the

total to 20. The proposed development will result in the loss of significant amounts of

hedgerow (2.7km) and 30 trees, albeit with replacement planting in excess (4.86km and 57

trees) of those removed. Lesser Horse[s]hoe Bat are a Qualifying Interest for Old Domestic

Building (Keevagh) SAC, Dromore Woods and Lough SAC and Old Domestic Building, Ryland

SAC which are within the foraging zone of the proposed development.

87) The revised EIAR confirmed the loss of one Leisler’s bat roost which it identified as

a significant effect at a local scale. It is unknown how many trees with tree roost potential

are to be removed as this is not identified in the revised EIAR (p. 95). One of the trees on

the site is identified as having a high roost potential but it is unknown if this tree was

investigated to establish that fact or whether it is scheduled for removal. Impacts on bats

from loss of commuting and foraging habitats was identified as significant at a local scale.

88) A number of remediation/mitigation measures are identified at §7.6. There are

specific measures to mitigate impacts on Lesser Horseshoe Bats (p. 124), including the

planting of replacement hedgerows and trees at an early point in the project life-cycle and

the installation of low spill lighting.

89) In relation to structures involving known (Building 6C) or possible (Building BB 1B,

BB 4A-D, BB6A-B and BB 7) bat roosts it identifies the relevant mitigation as demolition only

taking place at certain times of the year pursuant to a derogation licence. The demolition

would only take place after additional surveying and restriction on access for bats. Additional

mitigation measures (pp. 131 and 132) are identified for the removal of trees, although the

number of trees with potential bat roosts are not identified. Compensatory measures are

identified at p. 143. The revised EIAR concluded that with the application of strict mitigation

measures there would be no significant effects on the environment,

90) The Board’s Inspector identified that

‘Bats: The farm buildings, and linear hedgerows and stone walls that traverse the site have

breeding, roosting, foraging and commuting potential for bats (incl. Lesser horseshoe, Brown

long-eared, Soprano & Common pipistrelles and Leisler’s bats), and several of the further

afield SACs and pNHAs are designated for Lesser Horseshoe Bat. The various EIAR desk-

top and site surveys confirm that the site and environs are frequented by bats, and although

some of the older farm buildings may also have roosting potential, the applicant confirmed

that no roosts were recorded during the surveys. The applicant should carry out a pre-

construction survey of the any buildings to be demolished and seek a Derogation Licence for

the safe and humane removal and relocation of any species present in the buildings. The

removal of mature hedgerows trees and stone walls would have an adverse impact on

foraging and commuting bats in the short term, however the proposed replanting would

reduce this impact in the long term, provided that the replanting takes place during Phase

1 and before the end of the first year of construction. The planting of local indigenous

hedgerow species should be required along with on-going monitoring to ensure that the

replacement hedgerows mature to a satisfactory level Given that a 10-year permission is

being sought, any delay in or prolongment of the replacement planting could have significant

adverse impacts on bat populations in the area. Subject to compliance with the above

requirements, I am satisfied that bats would gradually habituate with no significant adverse

long-term impacts anticipated. Any on-site artificial lighting should be designed, installed

and managed in a manner that does not interfere with bat activity whilst also ensuring public

safety’”

41. The critical sub-grounds relate to a single issue as follows:

“91) This is completely incorrect. The Notice Party identified 20 roosts on the site in

buildings, with 17 trees identified as having roost potential and the loss of one confirmed

roost in a residential building. The Inspector identified that bats used the site for feeding

and foraging and may be affected by the demolition of the farm buildings and that (p. 98)

‘A Derogation Licence would be sought to ensure the humane relocation if required’. In the

Inspector’s summary the impacts on bats are not identified as involving roost loss (pp. 113

and 133) ‘changes to the vegetation on the site, loss of foraging habitat and disturbance to

otters, badgers, birds and bats’. The Inspector’s Report in respect of the Substation contains

similar errors, at pages 34-35.

92) The Applicants makes a number of points.

93) Firstly, the Board’s Inspector’s Reports (with whom the Board did not disagree) each

contain a significant and material error. The Notice Party did identify roosts on the site of

the proposed development and the proposed development will involve the loss of at least

one identified roost and the potential loss of other roosts in buildings and trees. The Board

was obliged but failed to consider the significance of the certain roost loss (and the other

potential roost losses) and Board’s conclusion of no significant effect on the environment is

based on material errors of law and of fact sufficient to vitiate the decision.”

42. The notice party phrases its point thus:

(i) the inspector’s factual error falls into the category of harmless error which was

immaterial in the overall context of the inspector’s consideration of the issues related

to bats (submissions para. 16); and

(ii) even if the error is one which might go to certiorari, the notice party submits that

its quashing would be entirely disproportionate and that the court should exercise

its discretion against quashing, in circumstances where, having regard to the

information in the EIAR regarding, inter alia, mitigation and compensation measures

for bat fauna, which were taken into account by the inspector and the board in

conducting an EIA, the outcome would have been no different if the inspector hadn’t

made the error (para. 17).

43. These two formulations in fact come to the same thing and can best be summarised as being

a “harmless error” point.

44. The parties’ positions as recorded in the statement of case are summarised as follows:

“Notice Party’s position:

(i) The Inspector’s mistake, underlined in the extract set out at paragraph 90 of the

Statement of Grounds, overlooked the fact that the revised June 2022 EIAR had indicated

the presence of a single Leisler bat roost in Building 6C which required to be removed as

part of the development.

(ii) The single bat roost identified in Building 6C in March 2022 was documented in the

revised EIAR. The roost was of local importance only and too small for a nursery roost.

Comprehensive mitigation measures were included in the EIAR and are required to be

implemented of foot of conditions attaching to the Data Cent[re] permission. The EIAR

concluded there would be no significant residual effects on biodiversity. The public was not

misled as the information was available in the amended EIAR.

(iii) There is a suggestion in paragraph 91 of the Statement of Grounds of further errors

by the inspector in failing to identify 20 bat roosts and in failing to note the presence of 17

trees with potential roost features (PRFs), It is not accepted that these were errors and even

if they were, they could not be characterised as material as the roosts and PRFs in question

were to remain in situ. However, in so far as roosts were identified on the site, none were

required be removed to facilitate the proposed development, other than the single bat roost

in Building 6C. Therefore, the identification by the Applicants of the existence of roosts

which would not be affected or disturbed by the proposed development is not of any potential

significance to the EIA which the Board was obliged to carry out. Further, insofar as 17 trees

were identified as having roost potential, there is no evidence of the Inspector having made

an error regarding these. Moreover, these tree PRFs are to be the subject of mitigation

measures as detailed in the EIAR and herein, and which are binding on Art pursuant to

condition 3 of the Data Centre permission.

(iv) Properly considered, the Inspector’s factual error falls into the category of harmless

error which was immaterial in the overall context of the Inspector’s consideration of the

issues related to bats in respect of a development on a site of 60 hectares. The error did

not affect the substance of the Inspector’s (or the Board’s) overall assessment of biodiversity

issues, including in relation to bat fauna, as part of the EIA. Given that the Inspector and

the Board accepted the conclusion in the EIAR, which was reached in the knowledge of the

existence of the single Leisler bat roost in Building 6C which would need to be removed as

part of the development, the Board’s decision would have been no different had the Inspector

not made the factual error, as recorded on page 74 of her report.

(v) The immateriality of the error in the overall context of the assessment does not

require any intervention on the part of the Court. The question of the Board’s decisions

being quashed on the basis of this immaterial error ought not to arise.

(vi) The Notice Party contends that the error in the Inspector’s report does not constitute

a basis for quashing the Board’s decision on the basis that it is immaterial, having regard to

the Inspector’s overall conclusions on the impact of the proposed development on bat fauna.

(vii) Alternatively, the Court should withhold relief on the basis of discretion, on the basis

that the Inspector’s mistake was a harmless error: see Carrownagowan Concern Group v.

An Bord Pleanála (No.3) [2024] IEHC 549 at §52, where Humphreys J. concluded that, by

reference to a mix of identified EU, national and UK judgments, there was nothing

controversial in proposition that errors that make no difference should not be quashed

‘particularly in a context where the evidence to that effect was unchallenged’.

(viii) In considering whether to quash on the basis of an admitted error, the matter could

be considered by reference to the material before the Board ‘as a whole’, which includes the

EIAR: Carrownagowan (No.3), paragraph 31.

(ix) In the circumstances, quashing the Board’s decisions would be entirely

disproportionate. In Eco Advocacy v An Bord Pleanála [2025] IEHC 15 at §§169-170,

Humphreys J. referring to the opinion of Advocate General Bobek delivered on 14 January

2021 in UH v An tAire Talmhaíochta Bia agus Mara and Others, ECLI:EU:C:2021:14

concerning the Court’s discretion to withhold relief: ‘the national court is doing nothing more

than carrying out its judicial function which is to find, for each dispute, the most appropriate

solution by looking at the specific context and all the relevant circumstances’.

(x) The context and the relevant circumstances as fully set out in the Notice Party’s

Statement of Opposition justify the withholding of certiorari on the basis of the Inspector’s

factual error. None of the Applicants (or any other party) took issue with the conclusions in

the EIAR of ‘no likely significant residual negative effects’ on, inter alia, bat fauna. Given

the Inspector’s conclusion in the same section of her report which overlooked the findings

in respect of Building 6C ‘that bats would gradually habituate with no significant adverse

long-term impacts anticipated’, it can be concluded that the Inspector’s conclusion would

have been no different had she not made the factual error in question.

Applicant’s position:

a) Bat roosts are strictly protected by virtue of Article 12(1)(d) of the Habitats Directive.

Any destruction of a bat roost is, by definition, a significant environmental impact.

b) The size of the bat roost is irrelevant as a matter of European law.

c) The Board did not consider the environmental impact of the destruction of the bat

roost.

d) The Board has correctly conceded because its decision is indefensible in the light of

the acknowledged error.

e) The Notice Party simply says ‘properly considered, the Inspector’s error falls into the

category of harmless error’ but it has, and can have no basis for that statement. The Notice

Party does not know what weight the Board would have put on the certain destruction of a

strictly protected roost and the phrase ‘properly considered’ is meaningless when the Notice

Party is not the decision maker.

f) Equally, the Notice Party simply says that the loss of a strictly protected bat roost is

‘immaterial’. As above any breach of Article 12 of the Habitats Directive is significant and

the question of materiality is for the Board and not the Notice Party. The Honourable Court

knows the view of the Board and should not lightly interfere with it.

g) The standard the Notice Party has to reach is to establish that the decision maker

would have definitely made the same decision absent the error. The Notice Party has not

done so.

h) It is correct that the Inspector and the Board accepted the conclusion of the EIAR.

However, in doing so they were unaware that the proposed development would result in the

destruction of a strictly protected bat roost. The ‘acceptance’ was based on a fundamental

mistake as to fact.

i) Furthermore, the carrying out of an EIA is a matter for the competent authority and

not the Notice Party and the Notice Party, respectfully, ignores that division of functions.

The competent authority carried out an EIA and that was premised on a fundamental mistake

that the proposed development would certainly lead to the loss of a strictly protected bat

roost.

j) The Notice Party’s reliance on Carrownagowan and Treascon are misconceived. In

both of those cases the evidence was that the Board’s errors had not resulted in any

environmental impact not being considered by the Board. In this case, the acknowledged

error has resulted in significant environmental impact – a breach of Article 12(1)(d) – not

being considered by the Board and relates directly to the Inspector’s ‘inflection point’ as

between potential and actual roost loss.

k) The Notice Party asserts ‘Given the Inspector’s conclusion in the same section of her

report which overlooked the findings in respect of Building 6C ‘that bats would gradually

habituate with no significant adverse long-term impacts anticipated’, it can be concluded

that the Inspector’s conclusion would have been no different had she not made the factual

error in question;’ the Applicant says this is incorrect for the very reason that the Inspector

overlooked the findings in respect of Building 6C, ie the destruction of the roost.

l) Separately, the acknowledged error means that the Board could not lawfully have

granted planning permission in the absence of a derogation licence having been granted

prior to the grant of development consent. The decisions of the Court of Justice in Namur

Est and Hellfire Massey are unequivocal that a derogation licence must be granted prior to

the grant of development consent. The argument that the Notice Party has to make is that

if the Board was (i) aware of the bat roost, (ii) it would have granted permission even without

the necessary derogation licence and (iii) that the Board would have breached European law

in so doing.

m) The Court should reject the implicit assumption that the Board would have granted

permission in breach of European law.”

The law in relation to harmless error

45. The law in relation to harmless error and discretion can be summarised as follows:

(i) A decision should not be quashed for error (including in application of EU

law) if the error was harmless and did not materially affect the result: Walton v.

Scottish Ministers [2012] UKSC 44, [2013] P.T.S.R. 51; judgment of 7 November

2013, Gemeinde Altrip and Others v Land Rheinland-Pfalz, C-72/12,

ECLI:EU:C:2013:712; R (Champion) v. North Norfolk District Council [2015] UKSC

52, [2015] 1 W.L.R. 3710; Canterbury City Council v. Secretary of State for Housing

Communities and Local Government [2019] EWHC 1211 (Admin.), [2019] 5

W.L.U.K. 225; R. (Hudson) v. Windsor and Maidenhead Royal Borough Council

[2021] EWCA Civ 592, [2021] 1 W.L.R. 5588 (Coulson L.J. at §§77-78); Sliabh

Luachra Against Ballydesmond Windfarm Committee v. An Bord Pleanála [2019]

IEHC 888, [2019] 12 JIC 2017 (Unreported, High Court, McDonald J., 20th December

2019); opinion of Advocate General Bobek delivered on 14 January 2021, UH v An

tAire Talmhaíochta Bia agus Mara and Others, ECLI:EU:C:2021:14; Reid v. An Bord

Pleanála (No. 2) [2021] IEHC 362, [2021] 10 JIC 0606 (Unreported, High Court, 6th

October 2021) at §53; Heather Hill Management Company CLG v. An Bord Pleanála

[2022] IEHC 146, [2022] 3 JIC 1603 (Unreported, High Court, Holland J., 16th March

2022) at §257 et seq. and §326(d) and (e); Concerned Residents of Treascon and

Clondoolusk v. An Bord Pleanála [2022] IEHC 700, [2022] 12 JIC 1609 (Unreported,

High Court, 16th December 2022) at §80; Toole v. Minister for Housing (No. 6)

[2023] IEHC 592, [2023] 10 JIC 3102 (Unreported, High Court, 31st October 2023)

at §39; Eco Advocacy v. An Bord Pleanála [2025] IEHC 15 (Unreported, High Court,

15th January 2025). The term “procedural defect” in Altrip has an autonomous EU

meaning which is not limited to narrow technical issues that do not include errors in

relation to the facts – the phrase covers any defects committed in the impugned

procedure: see for example the opinion of the Advocate General Cruz Villalón

delivered on 20 June 2013 in Altrip, ECLI:EU:C:2013:422 at paras. 44 and 45. In

Altrip the law in relation to environmental impact assessment was viewed as

procedural. In any event there is no logical or rational basis to limit the Altrip

doctrine to particular kinds of harmless error. Indeed generally speaking it would

trivialise judicial review and be an exercise in self-indulgence to quash decisions

because of things that make no difference, in the absence of a mandatory provision

that compels such an approach.

(ii) The determination of whether the error would have affected the result is one for the

court, which can act on evidence in the proceedings from an interested

party such as a developer – the CJEU says this expressly in Altrip para. 53. While

non-precedential, this point was seen as not raising doubt by the Supreme Court in

Carrownagowan Concern Group v. An Bord Pleanála [2025] IESCDET 9 (Charleton,

Collins and Donnelly JJ., 27th January 2025), para. 21: “Altrip – which was

concerned with the EIA Directive - clearly indicates that not every ‘defect’ will

necessarily have consequences that can possibly affect the purport of a decision to

approve a development: §49. While the defect in Altrip was characterised as

‘procedural’, the complaint appears to have been that the EIA carried out before

development consent was given was ‘inadequate’ (§16) which is effectively the

complaint made here (albeit, in the present case, in respect of council directive

92/43/EEC of 21 May 1992 on the conservation of natural habitats and of wild fauna

and flora (the habitats directive) rather than the EIA Directive). Altrip also makes

it clear that in this context a court may rely on evidence provided by the developer.

In light of the first of the questions which the Applicants tentatively suggest may

require a reference to the CJEU, it may be observed that the fundamental point in

Altrip was that a reviewing court might properly conclude that an error was

‘harmless’ without having to send the decision back to the original decision-maker”.

Accepting such evidence and making a finding of harmlessness is not a substitution

of the court’s views for those of the decision-maker, a standing in the latter’s shoes,

a trespass onto forbidden territory, or any other alarmist cliché: Altrip; R (Champion)

v. North Norfolk District Council; Canterbury City Council v. Secretary of State for

Housing Communities and Local Government; Carrownagowan Concern Group v. An

Bord Pleanála (No. 3) [2024] IEHC 549 (Unreported, High Court, 23rd September

2024) at §52. As the notice party submits here we “could not have a rational and

sensible system” if there was “some kind of exclusionary rule” that prevented the

court from receiving developer’s evidence. Such a rule would be inconsistent with

the Supreme Court’s finding in Ballyboden Tidy Towns Group v. An Bord Pleanála &

Ors [2024] IESC 4 (Unreported, Supreme Court, Donnelly J., 22nd February 2024)

that a developer can defend a permission even if the decision-taker does not.

(iii) Whether the test should be set at the level of the error being unlikely to make a

difference or one being satisfied that it would not make a difference may be semantic

in most cases other than the borderline. A working approach is to phrase it by saying

that the court should exclude a reasonable possibility that the error would

have made a difference to the actual outcome. Obviously an error would

definitionally make a difference to the wording of the reasoning but that can’t be a

barrier to the application of the doctrine because the doctrine would be meaningless

on that impossible condition. The CJEU puts the matter in terms of excluding doubt

(Altrip para. 53: “impairment of a right cannot be excluded unless, in the light of the

condition of causality, the court of law or body covered by that article is in a position

to take the view, without in any way making the burden of proof fall on the applicant,

but by relying, where appropriate, on the evidence provided by the developer or the

competent authorities and, more generally, on the case-file documents submitted to

that court or body, that the contested decision would not have been different without

the procedural defect invoked by that applicant”) which means reasonable doubt

because exclusion of all doubt is an impossibility. AA does not require the decision-

maker to disprove “any effect whatsoever” even those having “no appreciable effect”

or “hypothetical risk”: opinion of Advocate General Kokott of 29 January 2004 in

Landelijke Vereniging tot Behoud van de Waddenzee and Nederlandse Vereniging

tot Bescherming van Vogels v Staatssecretaris van Landbouw, Natuurbeheer en

Visserij, ECLI:EU:C:2004:60, paras. 102-106; judgment of 7 November 2018,

Holohan v An Bord Pleanála, C-461/17, ECLI:EU:C:2018:883 at paras. 33-37;

Holland J. in Heather Hill Management Company CLG v. An Bord Pleanála [2022]

IEHC 146, [2022] 3 JIC 1603 (Unreported, High Court, 16th March 2022), citing R

Mynydd Y Gwynt Ltd v The Secretary of State for Business, Energy and Industrial

Strategy [2016] EWHC 2581 (Admin), [2016] 10 W.L.U.K. 396, [2017] Env. L.R. 14

(at para. 259). Absence of reasonable doubt therefore does not mean “absolute

certainty” (paras. 44, 58, 59, and 61 of the CJEU's judgment of 7 September 2004,

Landelijke Vereniging tot Behoud van de Waddenzee and Nederlandse Vereniging

tot Bescherming van Vogels v Staatssecretaris van Landbouw, Natuurbeheer en

Visserij, C-127/02, ECLI:EU:C:2004:482 (Grand Chamber) and paras. 102 to 108 of

the Advocate General's opinion in Waddenzee, and the judgment in Holohan, at

paras. 33-37, Lord Carnwath in Champion at para. 41). Insofar as some caselaw

refers to whether it is “conceivable” that the decision could have been different (West

Cork Bar Association v. The Courts Service [2016] IEHC 388, [2017] 2 I.L.R.M. 281,

[2016] 7 JIC 0802 (Noonan J.); Baile Eamoinn Teoranta v. An Bord Pleanála [2020]

IEHC 642, [2020] 12 JIC 0405 (Unreported, High Court, Barr J., 4th December

2020)) those statements were fact-specific. In the way that the applicants here try

to generalise that as being some sort of mandatory test, the applicants’ wording is

not the optimum phrasing because it could lend itself to an erroneous reading that

any possibility of difference, no matter how tenuous, theoretical or unreasonable,

would be deadly to a permission. That can’t be the law in any workable sense –

virtually anything is “conceivable”, but not everything is reasonable.

(iv) An applicant has the burden to establish the existence of error, but the successful

demonstration of error shifts the onus. Therefore the onus of proof that a

demonstrated error was harmless lies not on an applicant but on the party

asserting harmlessness (Altrip para. 53). Hence if a developer’s affidavit

asserting harmlessness is properly controverted, that issue should be resolved in

favour of the applicant in the absence of cross-examination, applying RAS Medical

v. The Royal College of Surgeons in Ireland [2019] IESC 4, [2019] 1 I.R. 63, [2019]

2 I.L.R.M. 273, [2019] 2 JIC 0501 (Clarke C.J.).

(v) The determination of whether a particular error would have made a difference must

also be carried out by reference to the totality of the material before the decision-

taker, considered as a whole, as well as to such further material as the court may

receive in the proceedings: Carrownagowan (No. 3), para. 31.

(vi) The question of whether public participation was materially compromised is

also relevant: Altrip.

(vii) Where by contrast the error would have had a material effect on the outcome, any

breach of EU law should normally be remedied by certiorari. Any after-the-

event assessment which would allow a permission to stand should only be permitted

in exceptional circumstances: the judgment of 12 November 2019, Commission v

Ireland (Derrybrien Wind Farm), C-261/18, ECLI:EU:C:2019:955 (Grand Chamber).

(viii) Where the error relates to purely domestic law, then even if it would have had

a material effect, the court has a wider discretion although is not fully at large:

Independent Newspapers v. IA [2020] IECA 19 (Unreported, Court of Appeal, Murray

J., 22nd January 2020).

The facts in relation to the error

46. One point to note at the outset is that while there are hints in the relevant sub-grounds of

additional errors, no basis for this has been made out. It’s correct that 17 trees were of PRF status

(potential roost features), but they are not being removed.

47. The 2006 publication, McAney K., A conservation plan for Irish vesper bats – Irish Wildlife

Manuals, No. 20 (National Parks and Wildlife Service, Department of Environment, Heritage and

Local Government, Dublin, Ireland) referred to in the EIAR (referenced below and available at

https://www.npws.ie/sites/default/files/publications/pdf/IWM20.pdf) at pp. 23-24 notes highly

mobile behaviour even for nursery roosts (and the crack-in-a-wall roost we have here is too small

to house a nursery):

“Nursery roosts begin to form in April, the young are born in June and are on the wing a

month later. There is a dramatic decrease in the number of bats at the nursery roost once

the young are independent, as the adult females leave at this time, followed some weeks

later by the juveniles (Shiel & Fairley, 2000). Leisler’s bats emerge early in the evening,

often leaving the roosts before sunset; they emerge earlier on overcast nights (McAney &

Fairley, 1990; Shiel & Fairley, 2000). Forsyth (I. For[s]yth, pers. comm.), in a study of a

maternity roost in the Lagan Valley in Northern Ireland using passive identification

transponders and an infrared video camera found that females moved between 20 roost

sites a total of 120 times during a 6-year period; also, up to a quarter of the bats using the

roost would often not emerge on a given night.”

48. As averred to on behalf of the developer, the bat surveys which underpin information in

Chapter 7 (Biodiversity) in the consolidated EIAR were conducted based on the professional

judgement of expert ecologists from Mr Scott Cawley, with reference to published guidance on

survey methodologies, in particular Jan Collins, (2016), Bat Surveys for Professional Ecologists:

Good Practice Guidelines, 3rd edition (Bat Conservation Trust, London). The assessment considered

the overall “roost resource” in terms of PRFs, as distinct from merely considering confirmed roosts.

49. The 2016 Bat Conservation Trust guidelines

(https://cdn.bats.org.uk/uploads/pdf/Resources/Bat_Survey_Guidelines_2016_NON_PRINTABLE.p

df?v=1542281971 ) state that they have been endorsed by CIEEM (Chartered Institute of Ecology

and Environmental Management). I note that they state at p. 7 that they do not deal with mitigation

which is dealt with in separate 2004 guidelines (Mitchell-Jones).

50. In a discussion regarding roosts in trees, the guidelines state (p. 44):

“Surveying trees for bat roosts can be more challenging than surveying buildings because

many species that use trees for roosts are known to exhibit roost switching behaviour,

including barbastelle, Bechstein’s bat, Daubenton’s bat, Natterer’s bat, Leisler’s bat, noctule,

common pipistrelle and brown long-eared bat (Harris and Yalden, 2008, Dietz et al., 2011).

Some UK examples are as follows: Smith and Racey (2008) observed roost switching in

Natterer’s bat on average every 3 days; and Waters et al. (1999) observed roost switching

in Leisler’s bat between every 2 and 10 days. Frequent roost switching has also been

observed in barbastelle (Billington, 2003; Greenaway, 2001; Zeale, 2011) and Bechstein’s

(Palmer, 2013), two of our rarest species.

Additional difficulties inherent in finding tree-roosting bats are as follows: droppings do not

persist in trees in the same way as they do in buildings; some tree-roosting bats echolocate

very quietly (and sometimes not at all) and are therefore difficult to detect using bat

detectors; some tree-roosting bats emerge from their roosts very late and return very early;

and emergence surveys are often constrained due to the height of tree roosts above ground

level and restricted observation due to foliage or lack of light under the canopy. The chances

of discovering a roost, even if one is present, are relatively low. However, some of our

rarest species are heavily reliant on tree roosts.

Due to these limitations and from what is known about the ecology of tree-roosting bats, it

is arguable that all trees with bat roosting potential should be considered part of a resource

that will be used at one time or another by tree roosting bats in order to determine the

extent of impacts. Survey work on individual trees may confirm presence but is unlikely to

conclusively confirm absence. Precautionary measures are likely to still be essential during

works even where surveys have not identified occupancy…”

51. The Waters study cited is noted at p. 82 as Dean Waters, Gareth Jones, Mick Furlong,

“Foraging ecology of Leisler's bat (Nyctalus leisleri) at two sites in southern Britain”, 28 February

2006, Journal of Zoology, Volume 249, Issue 2, October 1999, pp. 173-180. The Journal is published

by the Zoological Society of London:

https://zslpublications.onlinelibrary.wiley.com/doi/10.1111/j.1469-7998.1999.tb00755.x. The

developer’s evidence is that the bats in question are “highly mobile” – and by reference to the Waters

study, if they switch roosts every two to ten days, what are the chances of the bat seen in March

2022 still being in the same roost – or even having been there as of the date of the board’s decision?

Hence the need for an overall roost resource approach.

52. The developer’s ecologists applied the recommended resource approach to the site

generally. As stated at para. 25 of the statement of opposition, duly verified:

“Given the tendency for bats to roost in small numbers (typically 1-5 bats) and their

tendency to switch roosts frequently, Scott Cawley determined on professional judgment

that the completion of roost emergence surveys on trees would be disproportionate in the

circumstances. Proportionality is an important aspect of bat surveys, as confirmed in section

2.2.5, page 15 of the BCT Guidance. The Notice Party’s professional ecologists determined

that a roost resource approach, together with the inclusion of a corresponding and

appropriate mitigation strategy relating to the loss of trees would be more appropriate in

relation to the project and would comprehensively address any potential for effects on

roosting bats.”

53. The statement of opposition continues:

“56. In carrying out an assessment of the direct and indirect effects on bats, the

precautionary principle (as provided for in the first paragraph of Article 191(2) TFEU),

requires the impact on the overall roost resource, in terms of trees and buildings with bat

roost potential, to be assessed. Logically, the Board has to assess the likely significant

effects on bats by reference to the date of likely impact, which is the date on which

construction is likely to commence rather than at the date of survey for the purposes of the

application.

57. At the date of the Board’s decision, the Board will not be in a position to assess with

certainty the number of bats that will be affected in terms of removal or disturbance of

roosts. The mobility of bats as a species and their frequent roost swapping habits, as noted

in the extract from the BCT Guidance (p.45) above, necessitates an assessment of the roost

resource, as a whole. It cannot be assumed that an actual bat roost which is recorded at

the date of survey will remain an actual bat roost at the date of the pre-construction survey.

Conversely, likely absence of occupation of a PRF by a bat or bats at the time of survey does

not necessarily determine whether the PRF is likely to become occupied at the date of

commencement of construction. For that reason, at the date of the Board’s assessment of

the impact on bats based on the survey information available, the Board is not in a position

to assess the precise number of actual bat roosts that will be revealed in the context of pre-

construction surveys and, accordingly, it is not in a position to precisely assess the direct

impacts on actual bat roosts. In these circumstances, the precautionary principle requires

a conservative approach to be taken by the Board, in assessing the likely significant effects

on the roost resource as a whole, rather than conducting an assessment based on the

number of actual bat roosts found at the date of survey or likely to be present at the date

of commencement of construction.”

54. The council requested and received further information on bat roost removal as follows (set

out in inspector’s report at para. 3.2):

“4. Biodiversity: Submit details of:- bat roost to be removed; impacts on mammal

mobility; seasonal hedgerow removal; impact on fen & flush habitats (NW); examples of

successful relocation of Calcareous grassland habitats; details of any habitat removal outside

of project footprint that could affect other species (incl. Lesser horseshoe bat); & assess

impacts of ash dieback on wooded areas – no loss of confirmed bat roosts, 30m buffer

provided, Derogation Licence sought if required; no mammals recorded within footprint &

ample surrounding support habitat; no hedgerow removal during bird breeding season; no

effect on wetland features, and water quality will be protected; details provided for grassland

habitat translocation; no habitat loss outside of project footprint; and adequate

compensatory tree planting.”

55. The EIAR of July 2021 states as follows in relation to Leisler’s Bat (pp. 67-69):

“Leisler’s bat

Transect surveys

Full details from each transect survey are provided above in Appendix 7.6, and locations of

each of the recorded Leisler’s bat calls are shown on Figure 7.19–7.20.

Leisler’s bats were the third most commonly identified species during transect surveys of

the proposed development, and calls were detected on all three transects carried out in

2020, and both transects in 2018. Areas with the highest levels of activity were along

Toureen Laneway, and in the wet grassland habitat adjacent to Toureen Lough.

Whilst this species was identified with higher numbers of calls in similar areas in 2018 i.e.

Toureen Laneway and Toureen Lough, activities levels in 2018 were a lot lower than activity

levels in 2020. Very little activity was recorded in the woodland in the north west, which

differs from ... all other bat species identified within the lands. This is likely due to the

feeding preferences of Leisler’s bat, as it is an exclusively aerialhawking species [n33:

Vincent Wildlife Trust, Ireland. Species profile – Leisler’s bat. Accessed here:

https://www.vincentwildlife.ie/species/leislers-bat], foraging up to heights of 30m.

Although this species was identified from calls along hedgerows and treelines, this likely just

reflects the walking route that was undertaken by surveyors, potentially resulting in missed

commuting and/or foraging Leisler’s bats that were feeding at a height over the fields and

pastures. In this essence, whilst treelines and hedgerows are important for this species,

they are less likely to be impacted directly from the removal of these features. High buildings

or structures could pose collision risk issues for this species as a result.

Static detector surveys

Leisler’s bat were detected on 14 out of 15 static detectors deployed in 2020, and 11 out of

14 in 2018. Activity levels were highest in the north of the site, along Toureen Laneway,

and along the southern mot hedgerow associated with the laneway. Little to no activity was

recorded in the west, particularly the south west, south of the woodland habitat. Static

detectors deployed in 2018, had significantly lower numbers of calls picked up on detectors,

however activity was highest along Toureen Laneway, and in the north of the site.

Roost emergence/re-entry surveys

There were no Leisler’s bat roosts identified within the proposed development site. Leisler’s

are predominantly tree roosting bats but can occasionally roost in buildings as nursery roosts

[n33]. Roost emergence/re-entry surveys on trees were not carried out.

Evaluation

Leisler’s bats were recorded in high numbers across the site, particularly in surveys carried

out in 2020. They are known to have a widespread distribution across the region, and in

Ireland (Roche et al., 2014), however Leisler’s bats tend to show a southern bias in their

distributions, with greater numbers occurring in the south west and east of the country than

in the north. Populations of this species have shown to be increasing in recent years.

Leisler’s are high flying bats, and as such, they may have been using areas not covered by

detectors (middle of fields etc.), and therefore potentially not identified. However, Leisler’s

bat calls are typically loud and can be heard from a significant distance away, and would

likely have been picked up by static and/or handheld detectors despite this. Given the high

suitability of the site for this species, and the increasing population trends, particularly in

the south west of the country, the local population of Leisler’s bat is valued as being of local

importance (higher value).”

56. The EIAR relied on the lack of confirmed roosts in the buildings, but noted that one building

had moderate potential and stated that a precautionary approach would be taken (p. 95):

“Myotis sp. and Leisler’s bat

There were no Myotis sp. or Leisler’s bat building roosts identified within the proposed

development site. The buildings within the site are suitable for roosting Myotis sp. Leisler’s

bat can also roost in buildings (especially as maternity sites), however evidence has shown

that they tend to roost in trees rather than structures or buildings [n52: McAney, K. (2006)

A conservation plan for Irish vesper bats. Irish Wildlife Manuals, No. 20. National Parks and

Wildlife Service, Department of Environment, Heritage and Local Government, Dublin,

Ireland].

As there are no buildings with confirmed Myotis sp. or Leisler’s bat roosts species

within the proposed development site there is no potential for likely significant effects

on the conservation status of these bat species to occur at any geographic scale as a result

of this potential direct impact of building loss.

Buildings that did not have confirmed roosts (i.e. BB 1B, BB 4A – D, BB 6A-C, and BB 7)

were all negligible - low potential farm buildings, with the exception of BB 7, which was

considered to be of moderate potential for roosting bats. These buildings will be

removed as part of the development. Although roosts were not identified in any of these

buildings, due to the high activity levels and numbers of roosting bats across the site, a

precautionary principle will be applied, and subsequent mitigation measures

implemented to ensure there are no risks of injury/mortality to local bat species

as a result of the proposed development.”

57. Section 7.3 of the EIAR sets out details of the assessment of impacts on bats. Section 7.6

relates to mitigation measures and 7.7 provides for compensatory measures (collectively running

from p. 118 to 144, dealing with all biodiversity impacts, not just bats). These include the following

at pp. 131-134:

“7.6.1.4 Bats

Measures to Protect Bats during the Removal of Suitable Roosting Sites

All bat species and their roost sites are strictly protected under both European and Irish

legislation including:

• Wildlife Act 1976 and Wildlife (Amendment) Act, 2000 (S.I. No. 38 of 2000)

• Council Directive on the Conservation of Natural Habitats and of Wild Flora and Fauna

1992 (Council Directive 92/43/EEC)

• European Communities (Birds and Natural Habitats) Regulations, 2011

It is an offence under Section 23 of the Wildlife Acts 1976-2017 and under Section 51 of the

European Communities (Birds and Natural Habitats) Regulations, 2011 to kill a bat or to

damage or destroy the breeding or resting place of any bat species. Under the European

Communities (Birds and Natural Habitats) Regulations it is not necessary that the action

should be deliberate for on offence to occur. This places an onus of due diligence on anyone

proposing to carry out works that might result in such damage or destruction. Under Section

54 of S.I. 477 of 2011, a derogation may be granted by the Minister where there is no

satisfactory alternative and the derogation is not detrimental to the maintenance of the

populations of the species to which the Habitats Directive relates at a favourable

conservation status in their natural range. Given that the proposed development will result

in the loss of [a confirmed bat roost], a derogation licence under Section 54 of S.I. 477 of

2011 will be required.

The following mitigation measures are proposed in relation to structures considered to have

the potential to support roosting bats:

• All structures that were confirmed as having potential for bat roosts will be reexamined

immediately prior to demolition to assess whether bats are present at the time of

demolition. This will be an all-night survey of these structures undertaken during

suitable weather conditions to determine if bats enter the building during the night or

early morning. If bats are present, then they will require exclusion from the property

over several nights or, if possible, bats present will be physically removed by hand by a

licensed bat specialist and placed in a bat box and then released in the evening after

capture. The number, type and location of bat boxes to be included can be found in the

Landscape and Biodiversity Management Plan. 15 bat boxes are proposed for installation

in the proposed development site.

• For structures which have not been confirmed as bat roosts that are due to be

demolished but are regarded to have potential for bats, a bat detector survey of the

property to be demolished will be carried out. If demolitions are proposed during

the period of May to August and a bat roost is confirmed to be present, the

proposed demolition will not be permitted. This will be an all-night survey

undertaken during suitable weather conditions to determine if bats enter the

building during the night or early morning. If bats are present, then they will

require exclusion from the property over several nights or if possible bats

present will be physically removed by hand by a licensed bat specialist and

placed in a bat box and then released in the evening after capture.

• Once structures containing roosts are deemed to be clear of bats, the bat

specialist will be on site to supervise the demolition procedure until the

structure is no longer deemed able to support a bat roost. This is because bats

may reenter a partially demolished structure overnight.

Measures to Protect Bats during Vegetation Clearance

The following mitigation measures are proposed in relation to those trees identified as having

potential to support roosting bats (Figure 7.23). Bats could occupy suitable roosting features

at any time prior to the commencement of works. Therefore, there is an inherent risk that

bats could be affected by the proposed felling works. Where possible, trees with PRFs should

be retained. Where this is not possible, the following mitigation procedures will be followed:

• Felling of confirmed and potential tree roosts will be undertaken during the periods of

April to May or September to October as during this period bats are capable of flight and

may avoid the risks from tree felling if proper measures are undertaken, but also are

neither breeding nor in hibernation

• Use of detectors alone may not be sufficient to record bat emergence and reentry in

darkness. Therefore, prior to felling of confirmed and potential tree roosts, an

emergence survey using infra-red illumination and video camera(s) and bat detectors

will be carried out on the night immediately preceding the felling operation to determine

if bats are present

• Where it is safe and appropriate to do so for both bats and humans, such trees may be

felled using heavy plant to push over the tree. In order to ensure the optimum warning

for any roosting bats that may still be present, the tree will be pushed lightly two to

three times, with a pause of approximately 30 seconds between each nudge to allow

bats to become active. The tree should then be pushed to the ground slowly and should

remain in place until it is inspected by a bat specialist

• Trees should only be felled ‘in section’ where the sections can be rigged to avoid sudden

movements or jarring of the sections Where remedial works (e.g. pruning of limbs) is to

be undertaken to trees deemed to be suitable for bats, the affected sections of the tree

will be checked by a bat specialist (using endoscope under a separate derogation licence

held by that individual) for potential roost features before removal. For limbs containing

potential roost features high in the tree canopy, this will necessitate the rigging and

lowering of the limb to the ground (with the potential roost feature intact) for inspection

by the bat specialist before it is cut up or mulched. If bats are found to be present, they

will be removed by a bat specialist licenced to handle bats and released in the area in

the evening following capture

• If any bat tree roosts are confirmed, and will be removed by the proposed felling works,

then a derogation licence will be required from the NPWS and appropriate alternative

roosting sites will be provided in the form of bat boxes.

Measure to control and reduce light spill during construction

During construction, the use of security lighting such as that around the construction

compound could impact on commuting/foraging territory, however night works will not be

undertaken during construction. During winter months when days are shorter, there may

be a temporary level of light spill from the construction compound either side of

sunrise/sunset. This will be during hibernation period for bats however, and impacts will be

minimal. Therefore, mitigation is recommended for the temporary impact of light spill of

bat species.

Security lighting at construction compounds or in active works areas in close proximity to

bat commuting and/or foraging areas will be designed in conjunction with the EcOW/bat

ecologist to minimise light spill. Measures to reduce light spill may include the following:

• the use of sensor/timer triggered lighting;

• LED luminaires will be used where possible due to their sharp cut-off, lower intensity,

good colour rendition and dimming capability;

• column heights will be considered to minimise light spill; and,

• accessories such as baffles, hoods or louvres will be used to reduce light spill and direct

it only where needed.

Measures to reduce impacts from habitat loss

The proposed development will result in a total loss of c. 2.7km hedgerows, and 30 trees;

therefore replacement planting is required to ensure that there will be no net loss of lesser

horseshoe bat foraging and commuting habitat as a result of the proposed development,

and to ensure there will be no impact on local bat species, See Section 7 of the NIS (Scott

Cawley, 2021), and Section 7.6.1.1 above. This will comprise of c. 4.86km of hedgerow and

57 trees within the proposed development site (see the Chapter 10 Landscape and Visual

Impact Assessment, and the Landscape Design Strategy for location map, planting schedule

and specific details of proposed species). Native hedgerow planting will include the following

species; Alnus glutinosa, Corylus avellana, Crataegus monogyna, Ilex aquifolium,

honeysuckle Lonicera periclymenum, Malus sylvestris, Prunus avium , Prunus spinosa, Rosa

canina, Samucus nigris, and Viburnum opulus. Tree planting will include semi-mature

species such as: Quercus petraea, Fagus sylvatica, Arbustus unedo, Pinus sylvestris, Betula

pendula, Sorbus acuparia, Prunus avium plena. There will also be woodland structure

planting on the peripheries of the site and of the buildings, which will total c. 58,567m2 of

planting, and 3300 trees per/ha. This will ensure the proposed development compiles with

Objective 14.11 of the Clare County Development Plan 2017-2023 (As varied), and the

requirement that there is no net loss of lesser horseshoe bat habitat within the proposed

development.

This proposed planting has been designed to ensure that connectivity for foraging and

commuting bats is maintained - i.e. along the peripheries of the site, and within the site

from the woodland in the north west to suitable foraging habitats such as Toureen Lough,

and along hedgerows in the north to woodland and wetland habitats in the east, also

ensuring connectivity is maintained to/from roost buildings.

Existing hedgerows along the southern boundary that are less species rich, will be enhanced

through additional planting of native species. The proposed planting will occur in phases.

with the earliest planting occurring along important foraging and/or commuting routes in

the north, south and east of the site, at pre-construction stage and prior to removal of any

habitats. This will ensure that suitable foraging and commuting habitat for bat species is

established prior to the removal of such habitat during the construction of the proposed

development; therefore maintaining the site’s suitability for local bat species. Cattle grazed

fields are known to have higher rates of bat activity than ungrazed grassland (Downs et al.

2010) [n60 Downs, N., & Sanderson, L. (2010). Do Bats Forage Over Cattle Dung or Over

Cattle? Acta Chiropterologica, 12(2), 349-358 [note – available at

https://www.researchgate.net/publication/232677814_Do_Bats_Forage_Over_Cattle_Dun

g_or_Over_Cattle]; therefore, in addition to the hedgerows and treeline planting, areas of

cattle grazed grassland will be maintained as they are currently in the east, north and west

of the site with additional hedgerows separating fields, to provide further suitable habitat for

lesser horseshoe bat.”

58. At p. 141:

“7.6.2.4 Bats

Measures to Control and Reduce Light Spill During Operation

A light spill model study of the proposed development site was undertaken by Hurley Palmer

Flatt (June 2021) to determine the effects of artificial light and Artificial Light At Night (ALAN)

on bats as a result of the proposed development and identify how to reduce or eliminate

ALAN onsite, based on information from both Eurobats Guideline No.8, the Institution of

Lighting Professionals (ILP) Guidance Note No.8. and Bat Conservation Ireland Guidance

Notes for: Planners engineers, architects and developers. The mitigation as described above

in Section 7.6.2.1, also applies for all bat species using the proposed development site.

To ensure important bat corridors are maintained throughout the site before, during and

after construction, a 30m dark zone buffer will be in place along hedgerows and treelines

within the site wherever possible, and along the Clare County Council Ecological buffer zones

(Figure 7.24).”

59. At p. 143:

“Hedgerows are a key habitat within the proposed development site, valued as being of local

(higher) importance, and forming a key network of green corridors across the site. The

retention of as many of these corridors as possible and the enhancement of the existing

green network through new additional corridors has been a key consideration in the design

of the landscape around the Data Centres. New woodland belts and hedgerows that provide

new and replacement connections across the site are utilised, with 4.86km of new native

hedgerow planting proposed, as well as c. 58,567m² of woodland planting. Only native

species, and species that are already found within the site, will be planted. The retention

and enhancement of existing hedgerows, with additional planting of native hedgerows will

provide commuting and foraging routes for local bat species across the site, and will maintain

access to/from roost sites and particularly active foraging areas of the site (Toureen Lough,

woodland in the north west, hedgerows in the east). These hedgerows will also provide

commuting corridors, foraging areas and suitable habitat for a range of other mammals,

birds, invertebrates, and reptiles.

There will be a loss of dry meadows and grassy verges within the footprint of the proposed

development. Whilst this habitat is valued as being of local (lower) importance based on

the common species found here and availability of this habitat in the wider environs,

compensation for the loss of this habitat is included. Meadow grasslands are proposed

around the edges of the Data Centres, with c. 5.5ha proposed. These grasslands will include

wildflowers such as Lotus corniculatus, Medicago lupulina, Hypochaeris radicata, Lythrum

salicaria, Silene flos-cuculi, Trifolium pratense, Agrostemma githago, and Succisa pratensis

(full list of species can be found in the Landscape Design Strategy Report. These meadow

grasslands will provide opportunities for a range of pollinators and other invertebrates, in

addition to provide habitat for foraging birds, bats and other mammals. Feature trees and

smaller tree species are also proposed within this habitat, the majority of which are seed or

fruit bearing, which will offer foraging habitat for birds and mammal species.”

60. At pp. 156-157 such measures are summarised in the context of impacts for AA purposes:

“Layout designed to protect and retain confirmed bat roost buildings

Demolition of structures/felling of trees following seasonal restrictions

Roost presence/absence surveys prior to demolition of structures/felling of suitable bat roost

trees

Soft felling of suitable bat roost trees

No night works will be normally undertaken during construction. Any lighting required during

construction will be minimal and will avoid suitable foraging/roosting areas. Lighting will be

off in normal circumstances and only used during emergencies

Planting of native hedgerows and woodlands prior to any removal of vegetation to ensure

commuting and/or foraging areas are retained throughout development and operation

Lighting during operation designed to be as close to 0 Lux as possible on sensitive bat

foraging and/or commuting routes, with lighting only used for emergencies at night and for

egress through the site using torches/headlights.”

61. The EIAR was revised in June 2022. Section 7.3 was amended to update the survey

outcomes by reference to the single bat and single roost in Building 6C.

62. Relatedly, a single sentence was added on p. 69 (this was the point the inspector

inadvertently overlooked):

“However; a Leisler’s bat roost with one bat was identified during daytime building

inspections during surveys in March 2022.”

63. The consolidated EIAR maintained the previous conclusion at §7.9 that “Considering the

elements included within the design of the proposed development (as described in the Project

Description), and the implementation of the mitigation measures proposed in the EIAR and the

associated planning application documents, to avoid or minimise the effects of the proposed

development on the receiving environment, no likely significant residual effects on biodiversity are

predicted”.

64. The applicants participated in the process and had available to them the consolidated EIAR,

which included information regarding the existence of the single Leisler’s Bat roost in Building 6C

which would require to be removed as part of the development (if still in being at that time). So

this isn’t a case where public participation was somehow compromised.

65. The applicants did not make any submission about the bat roost in Building 6C as an issue

at all, either before the council or the board, nor did they seek to suggest that it would make any

difference in the assessment of environmental impacts on biodiversity, or bat species in particular,

or challenge the conclusion of the consolidated EIAR of no significant residual impacts on bats. Nor

indeed did anyone else controvert that conclusion. That can’t be irrelevant to the issue at hand.

66. In submissions to the board, the Development Applications Unit (DAU) / National Parks &

Wildlife Service (NPWS) did not have concerns following the FI on bat roosts. The inspector records

(para. 3.6):

“Observations received from the following Prescribed Bodies: -

DAU/NPWS: No objection following receipt of FI in relation to: - bat roosts; mammal

mobility; seasonality of hedgerow removal; extent of habitat loss outside project footprint;

and impacts on wetland habitats with resultant mitigation; subject to several conditions (incl.

pre-construction surveys, habitat translocation, lighting & implementation of the Biodiversity

Management Plan).”

67. In section 7.6 on biodiversity the inspector expressly envisaged replanting as a mechanism

to mitigate the loss of roosts:

“National sites: The site is not located within or close to any designated National sites

although there are many NHAs and p/NHAs within a c.15km radius of the project. These

sites have been designated for a similar variety of habitats and species as the European

sites. Although there may be an aquatic connection between the Data Centre site and some

of the nationally designated sites, it is unlikely that the project would have an adverse impact

on them, subject to the implementation of the EIAR surface and groundwater water quality

protection mitigation measures and any recommended planning conditions (Refer to section

7.5 above). The replanting of the lost hedgerows and trees as per the landscaping proposals

and the Landscape and Biodiversity Management Plan would ensure that any qualifying

species (incl. birds & bats) from further afield sites would not be adversely affected in the

long term by a loss of breeding, roosting, foraging or commuting habitat.”

68. Section 7.6 went on – this is the bit that contains the error – to envisage measures to

address removal of bats present in the buildings:

“Bats: The farm buildings, and linear hedgerows and stone walls that traverse the site have

breeding, roosting, foraging and commuting potential for bats (incl. Lesser

horseshoe, Brown long-eared, Soprano & Common pipistrelles and Leisler’s bats), and

several of the further afield SACs and pNHAs are designated for Lesser Horseshoe Bat. The

various EIAR desk-top and site surveys confirm that the site and environs are frequented by

bats, and although some of the older farm buildings may also have roosting

potential, the applicant confirmed that no roosts were recorded during the surveys*.

The applicant should carry out a pre-construction survey of the any buildings to be

demolished and seek a Derogation Licence for the safe and humane removal and

relocation of any species present in the buildings. The removal of mature hedgerows

trees and stone walls would have an adverse impact on foraging and commuting bats in the

short term, however the proposed replanting would reduce this impact in the long term,

provided that the replanting takes place during Phase 1 and before the end of the first year

of construction. The planting of local indigenous hedgerow species should be required along

with on-going monitoring to ensure that the replacement hedgerows mature to a satisfactory

level Given that a 10-year permission is being sought, any delay in or prolongment of the

replacement planting could have significant adverse impacts on bat populations in the area.

Subject to compliance with the above requirements, I am satisfied that bats would

gradually habituate with no significant adverse long-term impacts anticipated. Any

on-site artificial lighting should be designed, installed and managed in a manner that does

not interfere with bat activity whilst also ensuring public safety.”

[*this is the error]

69. The inspector proposed a condition in relation to destruction of bat roosts at para. 11.0:

“5. The developer shall comply with the following nature conservation requirements:

a. A suitably qualified and experienced Project Ecologist shall be appointed to oversee

the protection of biodiversity during the construction phase, and for a monitoring period of

5 years following completion of development.

b. The Project Ecologist shall certify that the completed are compliant with the EIAR /

NIS mitigation measures and the following conditions.

c. No felling or vegetation removal shall take place during the period 1st March to 31st

August.

d. A pre-construction bat survey shall be carried out by a suitably qualified ecologist

during the active bat season.

e. Any destruction of bat roosting sites or relocation of bat species shall be

carried out by a suitably qualified ecologist under a Derogation Licence granted by

the Minister for Housing, Local Government and Heritage.

f. A pre-construction otter survey shall be carried out by a suitably qualified ecologist.

g. Any destruction or relocation of otter holts shall be carried out by a suitably qualified

ecologist under a Derogation Licence granted by the Minister for Housing, Local Government

and Heritage.

h. Mammal friendly fencing shall be installed during the construction and post

construction phases.

Reason: In the interest of biodiversity and nature conservation.”

70. In section 8.4, the biodiversity impacts were summarised by reference to the EIAR:

“EIAR sections 5, 6 & 7 and the associated Technical Appendices and reports dealt with: -

land, soils, geology & hydrogeology; hydrology & water quality; and biodiversity. Extensive

desk top studies & seasonal field surveys were undertaken, and AA Screening & NIS reports

were prepared (and revised). The EIAR described the receiving environment as comprising

low-intensity agricultural fields defined by trees, hedgerows & stone walls, with a variety of

soil types. There is an extensive wooded area parallel to the Ballymacahill / Spancelhill

Stream to the W, along with a smaller wooded area around Toureen Lough in the SW section.

The lands are underlain by limestone bedrock which is locally karstified, and there are several

small ponds, swallow holes & springs dotted around & adjacent to the site. The lands mainly

drain W and SW to the Ballymacahill /Spancelhill Stream which forms a confluence with the

downstream Garrus River, which ultimately discharges to the Fergus & Shannon Rivers (SAC

& SPA). The E section partly drains S towards the Tulla Road & beyond via underlying karst

features. The EIAR did not identify any sensitive sites within the project site, although there

are several European & national sites in the wider area which have been designated for a

variety of habitats & species (incl. waterbodies, wetlands, mammals, birds, bats & fish). It

recorded badger & otter activity within the site and environs, and the presence of the rare

Fen bedstraw in the N section. It noted that the site (incl. lands, hedgerows & farm

buildings) may be used by roosting, nesting, foraging & commuting birds & bats,

and that the on-site pods and nearby watercourse may provide support habitat for fish. The

EIAR did not predict any significant adverse impacts on biodiversity during the construction

and operational phases, subject to the implementation of mitigation measures to protect

ground & surface water quality, habitats & species. The consolidated EIAR and NIS did not

alter the conclusions to any significant extent.”

71. The assessment of this included:

“The site & environs are not covered by any sensitive natural heritage designations. The

site contains woodlands, wetlands, grasslands & hedgerows, it has an aquatic connection to

a nearby watercourse, and there is evidence that it is used / frequented by several

species of animal (incl. otter, badgers, birds & bats) for nesting, roosting, foraging

& commuting. The rare Fen bedstraw was recorded in the N fenland section. The

consolidated EIAR, NIS & CEMP contain several mitigation measures to protect water quality

& biodiversity.”

72. The sub-station inspector’s report repeats the error about no confirmed roosts at p. 34:

“Several species of bat frequent the site & environs and utilise the various habitats (incl.

hedgerows) and farm buildings within the overall data centre site for roosting, foraging &

commuting (although no roosts were recorded).”

73. However, she went on to envisage that there would be a need for the developer to apply an

approach that was “seeking a Derogation Licence if required to enable humane relocation”.

74. It follows from these references that the inspector was seized of the scenario whereby roosts

would be lost and considered that permission should be granted given the adequacy of mitigating

measures. It is a consequence of that that the existence of one additional roost isn’t a critical factor

changing the whole scenario – the anticipated existence of roosts is already accounted for by the

mitigation measures.

75. In granting permission, the board attached the following relevant conditions (emphasis

added):

“1. The proposed development shall be carried out and completed in accordance with

the plans and particulars lodged with the application, as amended by the further plans and

particulars received by the planning authority on the 25th day of February, 2022, the 10th

day of June, 2022 and by An Bord Pleanala on the 26th day of September, 2022, except as

may otherwise be required in order to comply with the following conditions. Where such

conditions require details to be agreed with the planning authority, the developer shall agree

such details in writing with the planning authority prior to commencement of development

and the proposed development shall be carried out and completed in accordance with the

agreed particulars.

Reason: In the interest of clarity.

...

3. The mitigation measures identified in the Environmental Impact

Assessment Report, the Natura Impact Statement and other plans and particulars

submitted with the planning application and appeal shall be implemented in full by

the developer, except as may otherwise be required in order to comply with the conditions

of this permission.

Reason: In the interest of clarity and the protection of the environment during the

construction and operational phases of the proposed development.

...

5. The developer shall comply with the following nature conservation requirements:

(a) A suitably qualified and experienced Project Ecologist shall be appointed to oversee

the protection of biodiversity during the construction phase, and for a monitoring period of

five years following completion of the development.

(b) The Project Ecologist shall certify that the completed development is

compliant with the Environmental Impact Assessment Report and Natura Impact

Statement mitigation measures and the following conditions.

(c) No felling or vegetation removal shall take place during the period 1st March to 31st

August.

(d) A pre-construction bat survey shall be carried out by a suitably qualified

ecologist during the active bat season.

(e) Any destruction of bat roosting sites or relocation of bat species shall be

carried out by a suitably qualified ecologist under a Derogation Licence granted by

the Minister for Housing, Local Government and Heritage.

(f) A pre-construction otter survey shall be carried out by a suitably qualified ecologist.

(g) Any destruction or relocation of otter halts shall be carried out by a suitably qualified

ecologist under a Derogation Licence granted by the Minister for Housing, Local Government

and Heritage.

(h) Mammal friendly fencing shall be installed during the construction and post

construction phases.

Reason: In the interest of biodiversity and nature conservation.”

76. Again the express reference to destruction of roosting sites is incompatible with the

argument that the board proceeded on the basis that there were no roosting sites. The basis was

that roosting sites might be identified prior to the development being carried out.

77. The developer’s statement of opposition is relevantly verified by Colm Clarke, Ecologist at

Scott Cawley Limited. The relevant averments are worth quoting at length (emphasis added):

“10. As set out at the commencement of Chapter 7 of the EIAR, on page 2, the purpose

of the report was to:

10.1 Establish and evaluate the baseline ecological environment, as relevant to the

proposed development.

10.2 Identify, describe and assess all potentially significant ecological effects associated

with the proposed development.

10.3 Set out the mitigation measures required to address any potentially significant

ecological effects and ensure compliance with relevant nature conservation legislation.

10.4 Provide an assessment of the significance of any residual ecological effects.

10.5 Identify any appropriate compensation, enhancement or post-construction

monitoring requirements.

11. The survey methodologies adopted by Scott Cawley with respect to bats are

documented in Chapter 7, pp. 10-16 of the EIAR. As is set out in the Notice Party’s

Statement of Opposition, the surveys were undertaken with reference to published guidance

on survey methodologies, in particular Collins, J. (2016), Bat Surveys for Professional

Ecologists: Good Practice Guidelines, 3rd edition (Bat Conservation Trust, London) (‘the BCT

Guidance’). A copy of the BCT Guidance is contained at Tab 3 of the Book of Exhibits.

12. At paragraph 24 of the Notice Party’s Statement of Opposition, an extract from page

44 of the BCT Guidance is set out, in the context of guidance on the completion of emergence

surveys on trees where a PRF is present, but where the presence of bats has not been

confirmed, it also includes the following statement in relation to the limitations of surveying

trees to identify bats. It states:

‘… Surveying trees for bat roosts can be more challenging than surveying buildings because

many species that use trees for roosts are known to exhibit roost switching behaviour,

including barbastelle, Bechstein’s bat, Daubenton’s bat, Natterer’s bat, Leisler’s bat, noctule,

common pipistrelle and brown long-eared bat (Harris and Yalden, 2008, Dietz et al., 2011).

Some UK examples are as follows: Smith and Racey (2008) observed roost switching in

Natterer’s bat on average every 3 days; and Waters et al. (1999) observed roost switching

in Leisler’s bat between every 2 and 10 days. Frequent roost switching has also been

observed in barbastelle (Billington, 2003; Greenaway, 2001; Zeale, 2011) and Bechstein’s

(Palmer, 2013), two of our rarest species.

Additional difficulties inherent in finding tree-roosting bats are as follows: droppings do not

persist in trees in the same way as they do in buildings; some tree-roosting bats echolocate

very quietly (and sometimes not at all) and are therefore difficult to detect using bat

detectors; some tree-roosting bats emerge from their roosts very late and return very early;

and emergence surveys are often constrained due to the height of tree roosts above ground

level and restricted observation due to foliage or lack of light under the canopy. The chances

of discovering a roost, even if one is present, are relatively low. However, some of our

rarest species are heavily reliant on tree roosts.

Due to these limitations and from what is known about the ecology of tree-roosting bats, it

is arguable that all trees with bat roosting potential should be considered part of

a resource that will be used at one time or another by tree roosting bats in order

to determine the extent of impacts. Survey work on individual trees may confirm

presence but is unlikely to conclusively confirm absence. Precautionary measures

are likely to still be essential during works even where surveys have not identified

occupancy…’

13. With regard to the last sentence of the second paragraph of the extract, whilst not

explicitly stated in the BCT Guidance, it is my professional understanding that this relates to

Myotis bechsteinii and Barbastellus barbastellus (the latter an Annex II species). These

species are both resident in Great Britain but are not resident in Ireland.

14. Paragraph 28 of the Notice Party’s Statement of Opposition refers to the Bat

Mitigation Guidelines for Ireland (Kelleher & Marnell, 2006) and a copy of the BCT Guidance

is contained at Tab 4 of the Book of Exhibits.

…

17. In Chapter 7 (Biodiversity) of the consolidated EIAR (submitted to the planning

authority in June 2022 as part of the clarification of the RFI response) at page 69 there is a

general observation made in relation to Leisler’s bats occasionally roosting in buildings as

nursery roosts. For the avoidance of doubt, it should be clarified that it is apparent from the

information furnished in the EIAR in Chapter 7 (Biodiversity), Section 7.3.3.5, Table 7.9 and

Table 7.10 p 49 and in text on p 69 relating to the size of the bat roost in Building 6 C that

it is too small to be used as a nursery roost. Furthermore, a roost emergence survey was

conducted to determine presence / likely absence of roosting bats at building 6C on 28 July

2020, e.g. during the season for detection of nursery/maternity roosts, and no bats were

observed returning to roost at the building (refer to EIAR Chapter 7, Table 7.6, pp 13-14 for

survey dates, and EIAR Chapter 7, Table 7.10, pp 49-50, and text on pp 94-95 for results

of survey).

18. The mobility of bats as a species and their frequent roost swapping habits,

as noted in the extract from the BCT Guidance (p.45) above, necessitates an

assessment of the roost resource, as a whole. It cannot be assumed that an actual

bat roost which is recorded at the date of survey will remain an actual bat roost at

the date of the pre-construction survey. Conversely, likely absence of occupation

of a PRF by a bat or bats at the time of survey does not necessarily determine

whether the PRF is likely to become occupied at the date of commencement of

construction. For that reason, at the date of the Board’s assessment of the impact on bats

based on the survey information available, the Board is not in a position to assess the precise

number of actual bat roosts that will be revealed in the context of pre-construction surveys

and, accordingly, it is not in a position to precisely assess the direct impacts on actual bat

roosts. In these circumstances, the precautionary principle requires a conservative approach

to be taken by the Board, in assessing the likely significant effects on the roost resource as

a whole, rather than conducting an assessment based on the number of actual bat roosts

found at the date of survey or likely to be present at the date of commencement of

construction.

19. Scott Cawley determined that a roost resource approach, together with the inclusion

of a corresponding and appropriate mitigation strategy relating to the loss of trees would be

more appropriate in relation to the project and would comprehensively address any potential

for effects on roosting bats.

20. In light of the growth in population referenced in the EIAR and having

regard to the significant numbers of Leisler’s bats on the site, the disturbance of a

single roost for an individual Leisler’s bat does not have the potential to have any

likely significant impact on the conservation status of the Leisler’s bat, nor even

on the individual Leisler’s bat having regard to the mitigation and/or

compensatory measures described in the EIAR and conditioned in the grant of

permission. This is reflected in the text in Chapter 7, Section 7.5.1.3 ‘Leisler’s bat’ pp 94-

95 ‘In the absence of any mitigation, the potential effects of bat roost loss on Leisler’s bat

would be significant, although in light of the small number of bats roosting in the building,

the scale of impact would be at the local level only. Potential impacts of loss of this roost

would not have an impact on the conservation status for this species as they are widespread

in the area, and across Ireland, and are a species listed as “Least Concern.” I wish to clarify

that although the plural is used in reference to the roost, only a single bat was observed

roosting in Building 6C.

21. As quoted above, in Chapter 7 (Biodiversity) of the Consolidated EIAR (at page 69),

‘Populations of this species have shown to be increasing in recent years.’ It is further stated

that ‘Given the high suitability of the site for this species, the Leisler’s bat roost identified,

and the increasing population trends, particularly in the south west of the country, the local

population of Leisler’s bat is valued as being of local importance (higher value).’ Further, as

noted in section 7.3.3.5 of the EIAR, the Leisler’s bat population within the zone of influence

of the project was valued as being of local importance (higher value), but not of county,

national or international importance.”

78. It’s true that, as the applicants complain, Mr Clarke isn’t an “independent” expert in the

sense of the caselaw, that is principally someone wholly independent of the developer.

79. If expert opinion evidence is not independent, the fact that it is uncontradicted is not

determinative because it may be inadmissible or of minimal weight (Duffy v. McGee [2022] IECA

254 (Unreported, Court of Appeal, Collins J., 7th November 2022) para. 25; Donegal County Council

v. Planree Limited [2024] IECA 300 (Unreported, Court of Appeal, Butler J., 18th December 2024)

paras. 141-147). The problem with the applicants’ argument on that basis is that we are not talking

about expert evidence in the legal sense here. A professional can comment as to the adequacy of

the work she actually carries out. The fact that it may not count as independent opinion evidence

doesn’t make it inadmissible. A scientist can give evidence about their own work without being an

independent expert in the sense of the caselaw. Thus an applicant is liable to be found not to have

discharged the burden of proof if evidence of this nature isn’t contradicted, even if one applies a

degree of caution and circumspection to the obvious context that a developer’s deponents are

defending their own work.

80. Holland J. said in Environmental Trust Ireland v. An Bord Pleanála [2022] IEHC 540, [2022]

10 JIC 0305 (Unreported, High Court, 3rd October 2022):

“102. It is, in my view, an all-but-inevitable commonplace that in planning and

environmental judicial review of the grant of planning permissions and other licenses, the

application for the permission or license will have been prepared with the assistance – indeed

largely by – experts whose affidavits later feature in the developer’s opposition in the judicial

review. I am unaware of any case in which their evidence has been excluded on that account

– and in fairness ETI does not say it should be – or deprived of weight on that account save

for specific reason. It is true that, inevitably, such experts generally ‘stand over’ on affidavit

their own work in making the relevant application. But it should be remembered – indeed

emphasised – that experts making or assisting planning applications owe, to the Board and

the public, similar duties of independence and professionalism to those they owe to the

courts. So, their ‘standing over’ in judicial review work product of that independence and

professionalism should be no surprise. The delay and expense in requiring developers to

generally retain a new expert team to defend a judicial review - inevitably on short notice –

would not be proportionate or justifiable.

103. It is, of course, entirely open to a party to impugn the credibility evidence of expert

evidence by reference to alleged conflict of interest or lack of independence but, as RAS

Medical stipulates, that must be generally done by cross-examination of the expert whose

credibility is impugned. That did not occur here. On affidavit and absent such cross-

examination it is impossible, at least generally, to ascribe greater or lesser weight to the

evidence of any expert as compared to another.”

81. To repeat, the objection just means that Mr Clarke’s opinion evidence about matters not

within his direct knowledge isn’t admissible. It doesn’t mean that all of his evidence isn’t admissible.

Like any witness, he can give evidence as to what he actually did and the logical and scientific basis

for that. That isn’t opinion evidence in the sense of the caselaw. On the contrary, it is permissible

evidence and is uncontradicted here.

82. There is perhaps an academically interesting question as to whether he can say that the

board would not have decided the matter differently. Is that merely a logical consequence of his

own evidence, or an impermissible opinion about someone else’s work?

83. On the facts here it is not necessary to rely on those averments. But if I had to rely on

them I would construe them as merely stating the logical consequence of his admissible evidence

about his own work, not as impermissible speculation. When Mr Clarke says that the board would

have decided the matter the same way, what he means is that the science was robust and covered

the scenario of a roost being in place as of the date of execution of the permission, so that a

reasonable decision-taker properly directing itself to the science would not have had any reason to

do anything differently had it known of the existence of a roost when granting permission. That is

just a permissible statement of a logical consequence of the factual situation, not impermissibly

opining about matters that are not established factually. But we can class that conclusion as obiter

because I don’t need to rely on such statements.

Application of the law to the facts

84. The critical features of the situation here are as follows:

(i) Bat behaviour involves frequent roost swapping, with the scientific material

suggesting roost swapping every two to ten days for Leisler’s Bat. Thus the only

valid approach to identifying impacts on bats is to look at the potential roost features

overall rather than place any undue emphasis on any one confirmed roost at a given

time, especially a roost for only one bat.

(ii) The bat surveys were not confined to established roosts, which would have been a

defective methodology. They complied with industry guidelines which involved

looking at PRFs, and hence the total roost resource. Thus the omission of reference

to a particular roost by the inspector does not, in the circumstances, affect the

overall conclusion.

(iii) The conclusion in the consolidated EIAR of “no likely significant residual negative

effects on biodiversity, following the implementation of mitigation measures that will

be undertaken” was reached taking into account the existence of the Leisler’s Bat

roost with one bat in Building 6C and having regard to the mitigation measures and

compensation measures set out in the EIAR, which were accepted by the inspector

as justifying the conclusion of “no significant adverse long-term impacts anticipated”

with respect to bats.

(iv) The mitigation measures in the EIAR, notwithstanding a lack of finding of roosts at

the time of the original surveys, clearly imply and envisage the potential for

establishment of roosts between the surveys and the carrying out of the

development. In one sense that’s exactly what happened as of March 2022. So

there isn’t anything unanticipated here.

(v) The applicants participated in the process and had available to them the consolidated

EIAR. This wasn’t a case where the applicants or the public generally were prevented

from participation on this issue.

(vi) Neither the applicants nor anybody else made any point about the single bat roost

or challenged the conclusion of no significant residual impacts.

(vii) Compliance with the mitigation measures in the EIAR, including the completion of

checks for roosting bats in buildings BB 1B, BB 4A-D, BB6A-B and BB 7 pre-

construction, has been conditioned as binding pursuant to condition 5, paras. (d)

and (e) of the data centre permission.

(viii) A finding of no material impact of the error flows in any event from the

uncontroverted status of the developer’s evidence on the issue.

(ix) The developer’s evidence, which is uncontradicted, that bats are highly mobile

implies that a single roosting bat in March 2022 will almost certainly not be at its

original location if the development were to happen now. All one can say about

whether any other bat is using the crack in the wall as a roost is that that is a

potential situation. Such a scenario makes it unreal to consider quashing the

permission because amongst many locations identified with roosting potential, one

roost was inadvertently overlooked by the inspector three years ago.

85. In the light of the foregoing, the conclusion that the inspector’s error was not material is

irresistible on the facts. The possibility of roosts subsequent to the initial surveys was built in and

accounted for, so whether a particular roost existed pre-permission or not was neither here nor

there. The fact that subsequent roosting happened doesn’t change the adequacy of the mitigation

measures, even if the inspector accidentally overlooked the March 2022 findings when referring to

the lack of confirmed roosts.

86. The applicants in submissions have erected an elaborate inverted pyramid of European and

domestic legal authority, but on these facts, this implausible construction is built on foundations of

sand. The first premise is the false one insofar as it assumes that there is anything impermissible

about the developer introducing new factual evidence to show that the error is harmless. The

applicants ignore the facts by two misconceived moves in particular. The first manoeuvre is by

saying that the inspector implicitly must have thought it was significant that there was a distinction

between potential and actual roosts. The problem there is that of course it is a point to note and

certainly would have affected the way the report was phrased – but that isn’t the test. The existence

of an actual roost would definitely affect the language of the report, but it is not decisive to the

actual outcome of the permission application for the reasons spelled out in detail above. The

applicants’ second move is to slap the clichéd label “forbidden territory” on Mr Clarke’s affidavit. But

it isn’t forbidden territory. Developer’s evidence in the proceedings – not just the consent process

– to show harmlessness was expressly allowed and envisaged by the CJEU in Altrip. The whole

doctrine of harmless error couldn’t work otherwise – if the court can’t receive new evidence and if

the only person that can evaluate them is the decision-taker, who by definition didn’t do so, then all

errors are potentially fatal no matter how apparently irrelevant. The cry of “forbidden territory” has

a sort of superficial plausibility but it disintegrates on even cursory contact with the CJEU’s

jurisprudence. Anyone who needs a reminder can be directed to para. 53 of Altrip (emphasis added):

“Therefore, the new requirements thus arising under Article 10a of [the EIA] directive mean

that impairment of a right cannot be excluded unless, in the light of the condition of causality,

the court of law or body covered by that article is in a position to take the view, without in

any way making the burden of proof fall on the applicant, but by relying, where

appropriate, on the evidence provided by the developer or the competent authorities

and, more generally, on the case-file documents submitted to that court or body, that the

contested decision would not have been different without the procedural defect

invoked by that applicant.”

87. The most important question is of course what is going to happen to our bat in Building 6C

or another bat, if any, at the crack-in-the-wall roost, if a roost still exists at that location. The

answer is, as stated in the EIAR (compliance with which is now conditioned): “If bats are present,

then they will require exclusion from the property over several nights or, if possible, bats present

will be physically removed by hand by a licensed bat specialist and placed in a bat box and then

released in the evening after capture”. That process was accounted for in the assessment of impacts,

so observing an actual roost doesn’t introduce any new factor that hadn’t been already considered

and taken into account. So the whole problem falls into the category of harmless error – something

that one can be satisfied about as not making a difference, to a level that excludes all reasonable

doubt.

88. To summarise the outcome as measured against the relevant points made by the parties

and set out in the statement of case I would comment as follows.

89. As regards the notice party’s position:

(i) It is relevant that comprehensive mitigation measures were included in the EIAR and

are required to be implemented on foot of conditions attaching to the data centre

permission. The EIAR concluded there would be no significant residual effects on

biodiversity.

(ii) It is also relevant that the public was not misled as the information was available in

the amended EIAR.

(iii) As regards the suggestion of the existence of roosts which would not be affected or

disturbed by the proposed development, this is irrelevant for present purposes and

there is no evidence of the inspector having made an error regarding these.

(iv) The inspector’s factual error falls into the category of harmless error which was

immaterial in the overall context of the inspector’s consideration of the issues related

to bats. The error did not affect the substance of the inspector’s (or the board’s)

overall assessment of biodiversity issues, including in relation to bat fauna, as part

of the EIA. Given that the inspector and the board accepted the conclusion in the

EIAR, which was reached in the knowledge of the existence of the single Leisler Bat

roost in Building 6C which would need to be removed as part of the development,

the board’s decision would have been no different had the inspector not made the

factual error, as recorded on p. 74 of her report.

(v) I agree that the immateriality of the error in the overall context of the assessment,

taken as a whole, does not require any intervention on the part of the court. The

question of the board’s decisions being quashed on the basis of this immaterial error

ought not to arise.

(vi) It is also relevant that none of the applicants (or any other party) took issue with

the conclusions in the EIAR of “no likely significant residual negative effects” on,

inter alia, bat fauna.

(vii) I agree that, given the inspector’s conclusion in the same section of her report that

“bats would gradually habituate with no significant adverse long-term impacts

anticipated”, it can be concluded that the inspector’s conclusion would have been no

different had she not made the factual error in question.

90. As regards the applicants’ position:

(i) Bat roosts are strictly protected by virtue of art. 12(1)(d) of the habitats directive.

I agree that any destruction of a bat roost is, by definition, a significant

environmental impact. However, we need to bear in mind that destruction occurs

at the point of execution of the permission and not at the point of grant of the

permission. The critical point is that any assessment that fails to take into account

the likely mobility of species between the surveys at the time of application and the

situation as of date of execution would be a defective and inadequate assessment.

Here, the assessment was carried out on the proper basis. Therefore the mitigation

measures allow for bat mobility across this period – there isn’t a significant or

material distinction in that methodology between a potential roost and a roost

observed in surveys. As the notice party says, “all of that was factored in”.

(ii) I agree that the size of the bat roost is irrelevant as a matter of European law at the

level of principle, but that isn’t relevant since I amn’t placing any reliance on that.

(iii) The argument that that the board did not consider the environmental impact of the

destruction of the bat roost has a dry literal sense in which it could be said to be not

entirely incorrect but is an example of the point that “the letter killeth but the spirit

giveth life”. Law needs to be primarily focused on substance rather than form, and

in substance the board did consider destruction of actual roosts insofar as it

considered potential roosts, and by providing for mitigation measures which

envisaged bat mobility as between roosts as of the date of the execution of the

permission. Furthermore that phrasing is disingenuous because it definitionally

excludes the doctrine of harmless error altogether. Omission to consider something

is simply branded as an utterly fatal jurisdictional failure even if the something was

in fact considered in substance.

(iv) The applicants’ argument that the board has correctly conceded because its decision

is indefensible in the light of the acknowledged error is just assertion and not a

reason to preclude the notice party from defending the permission.

(v) The applicants are totally incorrect to assert that the notice party can have no basis

for the statement that the error is harmless. The developer has set out the basis on

affidavit, which the applicants haven’t contradicted.

(vi) The argument that the notice party does not know what weight the board would

have put on the certain destruction of a strictly protected roost is a misconception.

That isn’t the test. If it was the test, it could never be satisfied where the board

wasn’t defending the decision and thus wasn’t putting in evidence. The test is

whether the court can be satisfied as to the exclusion of reasonable doubt regarding

a different outcome.

(vii) The argument that the phrase “properly considered” is meaningless when the notice

party is not the decision-maker is also a misconception. The question of how to

properly consider the decision is one for the court.

(viii) The argument that any breach of art. 12 of the habitats directive is significant is

correct. But that doesn’t get the applicants anywhere, because the whole point of

the present discussion is that the error in the inspector’s report doesn’t in itself give

rise to any breach of art. 12 of the directive for the reasons I have set out (by

reference to the matters being considered in this module).

(ix) The argument that the question of materiality is for the board and not the notice

party is misconceived. Whether a mistake is harmless (or immaterial – same thing)

is a question for the court.

(x) The argument that “The Honourable Court knows the view of the Board and should

not lightly interfere with it” fails to account for the Supreme Court’s decision in

Ballyboden. The fact that a decision-taker concedes does not hamper a notice party

from defending the decision or create some sort of higher threshold in itself.

(xi) As regards the argument that “The standard the Notice Party has to reach is to

establish that the decision maker would have definitely made the same decision

absent the error”, I have dealt with this above. Stirring phrases like “definitely”

carry the erroneous implication that a trivial or academic possibility is fatal to a

permission. The issue is whether reasonable doubt can be excluded – and it can be

here for reasons set out above.

(xii) As regards the argument that, in accepting the conclusion of the EIAR, the board

was unaware that the proposed development would result in the destruction of a

strictly protected bat roost and thus that the “acceptance” was based on a

fundamental mistake as to fact, the problem for the applicants is that the mistake

wasn’t “fundamental” given the precautionary nature of the approach taken. The

logic of the decision which allowed for the destruction of potential roosts inherently

encompassed the destruction of roots that were actually in use as of the date of

execution of the permission.

(xiii) As regards the argument that the carrying out of an EIA is a matter for the

competent authority and not the notice party, that’s correct but it doesn’t get the

applicants anywhere. The question of whether an error in the EIA would have

affected the result is one for the court which can draw on evidence from the

developer.

(xiv) The argument that the error has resulted in significant environmental impact – a

breach of art. 12(1)(d) – not being considered by the board is a misconception. If,

as here, the error would not make any difference, then by definition it doesn’t in

itself lead to a breach of art. 12. Whether there is a roost or a potential roost can’t

be an “inflection point” if the analysis and mitigation measures provide for both. The

applicants in effect just define “inflection point” in a way that means that any error

is on the wrong side of it.

91. Overall, the applicants’ arguments prove too much. A doctrine of harmless error that

depended on the decision-taker analysing what the decision would have been without the error is

no doctrine at all – that is an impossible standard.

Summary

92. The situation is simple – far simpler than the elaborate legal infrastructure erected by the

applicants would suggest. The central dynamic is as set out by the CJEU in a single paragraph in

Altrip at para. 53. I have applied that here and the decision has come through intact. In a piece of

summarisation that is both beautifully phrased and devastatingly lethal, the notice party in oral

submissions utterly demolishes the applicants’ case in just six words: “the potentiality necessarily

includes the actuality”. Potential roosts were accounted for in the surveys, the assessments and

the conditions – whether any were actually occupied at any given time doesn’t make any difference

to the outcome in terms of the issues being addressed in this module. That’s the point – anything

else is just commentary and detail.

93. In Eco Advocacy v. An Bord Pleanála [2025] IEHC 15 (Unreported, High Court, 15th January

2025) (para. 58(83)), I noted that the developer there destroyed the applicant’s principal case in

ten lines of transcript – their counterpart here has smashed even that record with an aphorism that

is going to stand in the annals for some time. This illustrates the reason why opposition to time-

limited hearings generally or the expedited procedure in particular is so utterly wrong-headed. What

wins cases is articulating a good point, not articulating a large volume of words over a large volume

of pages of transcript. I understand the natural desire to keep doing what one has historically been

comfortable in doing, but the price of a fossilised, conservative, inflexible mind-set is prohibitively

high when it comes to dealing with a situation whereby limited resources require a rationing of court

time. The issue isn’t quantity of submissions – to complain about limiting that is squawking down

the wrong tree. The issue is quality of submissions. Let nobody say that compact and time-limited

advocacy equates to ineffective advocacy.

94. Whether, and to what extent, the applicants can make headway on the derogation licence

issue or any other issue is for another day and for other parties to join in considering.

95. For a certain type of observer, the fate of a single roost containing a single bat will be viewed

as a trivial basis for a debate about the validity of the planning permission. That is perhaps

understandable at a superficial level but is a misconception. Obviously the issue isn’t trivial if you

are the bat. Nor is the protection of species and habitats generally a trivial matter. Nor is compliance

with EU law. W.B. Yeats anticipated the attitude of the trivialisers in “September 1913” when he

described those who “add the halfpence to the pence/ And prayer to shivering prayer”. A rather

nobler attitude was articulated by Kenneth Clark (also as it happens, a Yeats enthusiast), who asked,

standing in the baroque, high-ceilinged, Naval Hospital in Greenwich: “What is civilisation? A state

of mind where it is thought desirable for a naval hospital to look like this and for the inmates to dine

in a splendidly decorated hall” (Civilization (London, BBC and John Murray, 1969) p. 215). He went

on to suggest that accountants would never permit such superfluity of effort nowadays (p. 220).

The fact that all parties in the present proceedings, and particularly the developer’s professional and

ecological advisers, have concerned themselves so assiduously with the outcome for our bat and its

roost shows that, despite everything, as far as the state of civilization in this country is concerned,

all is not yet completely lost.

96. In outline summary, without taking from the more specific terms of this judgment:

(i) The order for modularisation has the effect that the impact of the lack of a prior

derogation licence on the materiality of the error is an issue for Module II. The

present module has to proceed on the assumption that the decision is valid other

than in respect of the matters pleaded at sub-grounds 91 to 93.

(ii) A decision should not be quashed for error (including in application of EU law) if the

error was harmless and did not materially affect the result.

(iii) The determination of whether the error would have affected the result is one for the

court, which can act on evidence in the proceedings from an interested party such

as a developer.

(iv) The test is that the court should exclude a reasonable possibility that the error would

have made a difference to the actual outcome.

(v) An applicant has the burden to establish the existence of error, but the successful

demonstration of error shifts the onus. Therefore the onus of proof that a

demonstrated error was harmless lies not on an applicant but on the party asserting

harmlessness.

(vi) The determination of whether a particular error would have made a difference must

also be carried out by reference to the material before the decision-taker, considered

as a whole, as well as to such further material as the court may receive in the

proceedings.

(vii) The question of whether public participation was materially compromised is also

relevant.

(viii) Where, by contrast, the error would have had a material effect on the outcome, any

breach of EU law should normally be remedied by certiorari. Any after-the-event

assessment which would allow a permission to stand should only be permitted in

exceptional circumstances.

(ix) Where the error relates to purely domestic law, then even if it would have had a

material effect, the court has a wider discretion, although is not fully at large.

(x) Applying that here, bearing in mind the highly mobile nature of the bats concerned,

the comprehensive roost resource methodology that adopted a precautionary

approach to both potential and actual roosts, the availability to the public during the

process of the amended EIAR which had the latest survey material, the lack of any

submissions from the applicants or anyone else on this issue, the comprehensive

mitigation measures, the fact that these mitigation measures have been conditioned

in the permission granted, the logic of the inspector’s conclusions and the

uncontested evidence from the developer’s professional adviser, reasonable doubt

as to whether the actual outcome would have been different without the error has

been excluded.

97. In concluding, I can note that as far as the parties appear to be aware this case is a modest

piece of recent legal history in that no previous developer in the State has succeeded in

demonstrating as misconceived an objection that the board was prepared to concede.

Order

98. For the foregoing reasons, it is ordered that:

(i) the proceedings be dismissed insofar as concerns Module I (sub-grounds 91-93

insofar as they are premised on the other grounds not having merit);

(ii) the matter be listed on Monday 31st March 2025 for mention to arrange the

processing of Module II (all remaining grounds, subject to contrary submission)

including by way of directions as to dates for filing of further papers);

(iii) subject to contrary submission within 7 days, there be no order as to the applicants’

costs in Module I;

(iv) subject to contrary submission within 7 days, the notice party’s costs be reserved,

on the basis that such costs if awarded would apply by way of set-off only (not

leaving a positive balance against the applicants at a level that would be prohibitively

expensive); and

(v) the perfection of the order be postponed pending the outcome of the final module.