High Court refuses Meta's motion to join preliminary issue trials with LinkedIn appeal due to procedural burden and existing precedent.

THE HIGH COURT

[2025] IEHC 631

Record Number 2024/533MCA

Record Number 2025/6 MCA

META PLATFORMS IRELAND LIMITED

Appellant

-and-

THE DATA PROTECTION COMMISSION

Respondent

EX TEMPORE RULING of Ms Justice Nessa Cahill delivered on 31 October 2025

INTRODUCTION

1. This is an application by Meta Platforms Ireland Limited (“Meta”) in one of its nine statutory appeals that is pending against the Data Protection Commission (“the DPC”), specifically the appeal bearing record no. 2024/533 MCA (the “Passwords Appeal”).

The following orders are sought:

(1) An Order pursuant to Order 25, rule 1 of the Rules of the Superior Courts 1986, as amended, directing a trial of the preliminary issues specified in the Schedule.

(2) Alternatively, an Order pursuant to Order 34, rule 2 of the Rules of the Superior Courts 1986, as amended, directing a trial of the preliminary issues specified in the Schedule hereto.

(3) Further, a direction that a trial of the preliminary issues specified in the Schedule hereto take place at the same time as, or immediately after, the hearing of the preliminary issues fixed by this Honourable Court for hearing on 2 December 2025 in proceedings bearing the title Linkedln Ireland Unlimited Company v. Data Protection Commission; High Court Record Number 2024/580 MCA (“the LinkedIn Appeal”).

2. Meta has confirmed that the purpose of the Motion focuses on the third of these reliefs, the application for directions to have the proposed preliminary issues listed for hearing at the same time or immediately after the trial of preliminary issues in the LinkedIn proceedings that is fixed for hearing on 2 December 2025 (and which has been so fixed since 25 June 2025).

3. A Notice of Motion filed was filed on 3 October 2025. The affidavit of Ms Gráinne Varian was sworn on 2 October 2025. The replying affidavit of Mr. Damien Young was affirmed on 21 October 2025. The replying affidavit of Ms. Varian was sworn on 24 October 2025.

4. An identical motion was issued in another appeal, bearing record no. 2025/6 MCA (the “Token Breach Appeal”) which arises from a decision of the DPC made on 2 December 2024 (the “Token Breach Decision”) pursuant to section 111 of the Data Protection Act 2018 (“the 2018 Act”) and Article 60 of Regulation (EU) 2016/679 (“GDPR”).

5. At the hearing of this Motion on 28 October 2025, counsel for Meta confirmed that the Motion for the trial of preliminary issues and associated reliefs was being progressed in the Passwords Appeal only.

THE PRELIMINARY ISSUES

6. The four preliminary issues to be addressed were the following:

(1) Is the appellant entitled to appeal the entire Decision under section 142 of the Data Protection Act 2018 or are there aspects of the Appeal which can only proceed as an appeal under section

150 of the Act?

(2) What type of appeal does section 142 of the Data Protection Act 2018 provide for and what is the standard of review/assessment to be applied by the Court in an appeal under section 142 having regard to all the circumstances including the DPC's role as a supervisory authority under the GDPR and the fact that the Decision was adopted in accordance with Article 60 of the GDPR?

(3) If there are aspects of the Appellant's Appeal which can only proceed as an appeal under section

150 of the Data Protection Act 2018, does a different standard of review/assessment apply in an appeal under section 150 of the 2018 Act and if so, what is the standard of review/ assessment having regard to the aforesaid matters?

(4) Having regard to the answers to the foregoing questions is the Appellant entitled to rely on evidence adduced and/or arguments made in the Appeal which were not already adduced or made to the DPC during the inquiry process and if so in what circumstances and to what extent?

BACKGROUND

7. The background to this motion is set out in the grounding affidavit of Ms Varian. She outlines the background and the various statutory appeals and judicial reviews that are pending, emphasising heavily the importance of the preliminary issues for these proceedings.

8. In summary, the Passwords Appeal is in respect of a decision of the respondent made on 26 September 2024 (the “Passwords Decision”) pursuant to section 111 of the Data Protection Act 2018 (as amended) and Article 60 of the GDPR.

9. The Passwords Decision was made in an own-volition inquiry commenced on 24 April 2019 under section 110 of the 2018 Act. In the Passwords Decision, the DPC found that Meta had infringed Articles 33(1) and 33(5) GDPR and failed to comply with the requirements of Article 5(1)(f) and Article 32(1) GDPR. The DPC issued a reprimand pursuant to Article 58(2)(b)

GDPR and imposed administrative fines in the total amount of €91 million.

10. In its opposition papers in both the Passwords Appeal and Token Breach Appeal, the DPC has put in issue the type of appeal provided for by section 142 and/or section 150 of the 2018 Act, the scope of appeal provided for by these provisions, and the standard of review which applies.

11. Meta’s position is that the interpretation of sections 142 and 150 of the 2018 Act contended for by the DPC in the DPC's Statutory Appeal Statement of Opposition is incorrect, particularly when regard is had to the obligation to interpret these provisions in a manner compatible with Articles 34 and 37 of the Constitution, Article 6 of the European Convention of Human Rights

(the “ECHR”) and Articles 41, 47 and 48 of the Charter of Fundamental Rights of the EU (the “Charter”).

12. There are judicial review proceedings mirroring each of the statutory appeals, but also challenging the validity of certain provisions of the 2018 Act, having regard to the Constitution, the ECHR and the Charter, and, as such, are not suitable for determination by way of a statutory appeal.

13. The interpretation of sections 142 and 150 of the 2018 Act is an important aspect of the statutory appeals and the judicial review. Ms Varian states that there are 9 statutory appeals pending to which Meta or its related companies are party.

14. On 25 June 2025, the preliminary issues that are now identified by Meta as suitable for preliminary determination were fixed for hearing on 2 December 2025 in the LinkedIn Appeal.

15. The following agreed directions were put in place in the LinkedIn Appeal:

(1) The appellant is to deliver submissions by 24 September 2025.

(2) The respondent is to deliver submissions in response by 29 October 2025.

(3) The State respondents are to deliver submissions by 14 November 2025.

(4) The indices to the agreed Book of Authorities and papers for the hearing are to be agreed by 21st November 2025.

16. It was also part of that order that the Attorney General (the “AG”) be entitled to participate in the trial of the preliminary issues on the basis those issues are relevant to the issues which arise in the related judicial review proceedings in the LinkedIn Appeal. It was ordered that the AG be served with a copy of the Motion papers and be entitled to participate in the trial of the preliminary issues. On this basis, the AG was also served with the papers for this motion and represented at the hearing before me.

17. The DPC Opposition Papers were delivered in the Passwords Appeal on 30 July 2025.

18. On 5 August 2025, Meta was informed by letter that the preliminary issues were listed for hearing in the LinkedIn proceedings and that the DPC regarded it as unnecessary and inappropriate for any similar motion to be issued by Meta. It is said that Meta was aware since

18 July 2025, having received the statement of opposition in the Token Breach Appeal, that such preliminary issues had been issued for hearing in the LinkedIn Appeal.

19. On 11 September 2025, Meta indicated in correspondence its intention to issue a motion for the trial of the preliminary issues at the same time or after the LinkedIn Appeal.

20. On 2 October 2025, Philip Lee, on behalf of the DPC, confirmed that expert evidence was being sought to be introduced in the LinkedIn Appeal. This motion issued on 3 October 2025.

PARTIES’ POSITIONS

Overview

21. The essential conflict between the sides hinged on the question of whether Meta needs to or should be heard, in the context of the determination of the preliminary issues that are currently listed for hearing on 2 December 2025 in the LinkedIn Appeal.

22. The position of Meta was that this is akin to a “pathfinder” situation, and that there are relevant factual, evidential considerations in Meta’s Passwords Appeal which would assist the Court in determining the preliminary issues. Particular emphasis is placed on expert evidence which Meta is seeking to adduce in the context of its statutory appeal in the Passwords Appeal. In the affidavits and written submissions of Meta, references are also made to the justice of the matter from Meta’s perspective, and the widespread importance of the issues for Meta. Those points are also emphasised in oral submissions.

23. Meta’s position is heavily disputed by the DPC and by the State, with both pointing to the need to conserve costs and time and avoid duplication in legal proceedings. It is asserted that Meta has no useful or necessary contribution to make to the resolution of the discrete questions of law which are currently listed for hearing in the LinkedIn Appeal. They contest the proposition that there could be any assistance from the introduction of additional facts, and contend that this clashes with the proposition that the matters identified are suitable for resolution as preliminary issues of law. It was contended that a litigant does not have the right to participate or be heard in relation to legal issues arising in other litigation.

Position of Meta

24. The position advanced in the grounding affidavit of Ms Varian on behalf of Meta is that, given the potential impact of the preliminary issues on Meta’s pending proceedings, as a matter of fairness, it would be appropriate for Meta to be permitted to make submissions to the Court on the scope and standard of appeal under sections 142 and 150 of the 2018 Act before the Court adjudicates on the preliminary issues in the Linkedln Appeal. It is further advanced that no procedural unfairness would be caused to either Linkedln or the DPC if Meta were to be granted this facility.

25. A further justification relied upon by Ms Varian was that “the Court itself would benefit from Meta's involvement and the additional point of view that its submissions and a consideration of the facts of this case will bring.” She cited the possibility that “the circumstances, facts and issues in the Linkedln Appeal may differ from those arising in these proceedings” and placed particular reliance on issue 4, noting that she was not aware whether expert evidence was proposed by LinkedIn at that point in time.

26. A third reason relied upon was the following:

“I am also advised by MPIL( Meta)’s legal advisers that there is every possibility that the nature of the arguments which would be advanced by reference to the underlying appeal papers to support MPIL's position on the scope and standard of appeal might well be different to the arguments which are put forward in the Linkedln Proceedings….”

27. In written and oral submissions, Meta highlighted that there is no dispute between the parties that the preliminary issues (i) are suitable to be determined as preliminary issues (ii) that they must be determined before the substantive appeals can be heard.

28. The position of Meta in submissions was that it would be of benefit to the Court to consider more than one fact pattern to ground the preliminary issues, as occurs in other pathfinder situations.

29. Heavy reliance was placed on the expert report or Mr Ioan Peters in the Password Appeal, and it was said that this adds an important evidential dimension that is relevant and would assist the Court in determining the preliminary issues and in construing the relevant provisions of the 2018 Act. Some emphasis was placed on issue 4 and it was said that it is relevant to know what type of evidence will be sought to be admitted and it is said that this will impact on how the appeal process is interpreted and that it is relevant to the determination of issues 1-3 also.

30. Meta placed particular emphasis on the question of whether the encryption measures put in place for a particular form of Facebook access (“Facebook Lite”) was in compliance with

Article 32(1) GDPR, with further emphasis being placed on the need to assess what the “state of the art ” was.

31. On that point, the case Meta will make on the appeal is that the DPC failed to assess what was the state of the art in this area and Meta will seek to adduce the expert opinion of Mr Ioan Peters on this point.

32. As regards the test for a preliminary issue, it was contended on behalf of Meta that issues are to be decided without reference to disputed facts but not undisputed facts. It was said that more than one “pathfinder” case can be used when it is appropriate to have regard to more than one fact pattern and that it would assist the court in having access to more than one factual permutation when deciding the preliminary issues.

33. The judgment of the Court of Appeal in Xerico v. Residential Tenancies Board [2025] IECA

202 (“Xerico”), was opened and it was pointed out that it concerned appeal provisions that bear a similarity to sections 142 and 150 of the Act and involved the hearing of preliminary issues with two pathfinder cases.

Position of the DPC

34. The position of the DPC was that Meta has no right to be heard on the preliminary issues in the LinkedIn Appeal and that it was inconsistent with the imperatives of efficiency and convenience to allow the application and would be a matter of concern for the administration of justice. It was said in the replying affidavit of Mr Young that the hearing of the same preliminary issues would add to the costs and burden imposed on the court and the DPC and not result in any savings or efficiencies.

35. Counsel for the DPC outlined the considerations to weigh in the context of a trial of a preliminary issue, first, the absence of any disputed issue of fact; second, the interests of efficiency and convenience and avoiding duplication; and, third, factors of overall justice.

These factors were identified by reference to the judgments of the High Court in Kalix Fund Limited v. HSBC Institutional Trust Service (Ireland) Limited [2010] 2 IR 581 (“Kalix”), Nyembo v. Refugees Appeals Tribunal [2006] IEHC 388 and L.M. v. The Commissioner of An Garda Síochána and others [2015] 2 IR 45 and are said also to be evident in the pathfinder cases.

36. Turning then to the so-called “pathfinder” cases, it was said that principles derived from those cases reflect good management approaches by the court with the object of avoiding duplication.

37. Particular emphasis was placed on the judgment of Clarke J. in Kalix and it was cited for the overriding proposition that, while there is an inherent jurisdiction of the Court as to the management of proceedings in which there is a significant factual and legal overlap, unnecessary duplication should be avoided to ensure efficiency and the conservation of court time (emphasises Kalix at para 49(A) and 50).

38. The case advanced by the DPC was that any facilitation of submissions by Meta on the preliminary issues that are currently listed for hearing on 2 December 2025 will mandate duplication because they are identical legal issues with no relevant factual distinction (given they are trials of net questions of law and the factual issue regarding late admission of expert evidence is already in play in the LinkedIn Appeal).

39. It was contended by the DPC that the reliance by Meta on the expert report undermined the application for trial of preliminary issues, was inconsistent with the position advanced on affidavit and that there was no clarity as to the other facts that would be relied upon. It was also contended that the content of the expert reports was irrelevant and the same general question of admission of such evidence at appeal arose in LinkedIn and did not warrant a separate pathfinder case. It was pointed out that emphasis on the facts would complicate the trial of the preliminary issues and increase costs.

40. The case of Xerico was distinguished on the basis that there were different factual scenarios in each case which warranted having two path finder cases.

41. Recourse was had to the overall interests of justice and the burden on the DPC was addressed in the affidavit of Mr Young. There was also an allegation of delay on the part of Meta and it was said that, given the directions for the LinkedIn motion had already been made, the delay is material.

42. The alternative approach proposed by Meta is that there could be a subsequent hearing after the determination of the preliminary issues in LinkedIn to see whether there are further preliminary issues which Meta wishes to bring forward.

Position of the AG

43. The position of the Attorney General, as articulated by counsel, was that this was an unorthodox application which cut across common law principles and could be disruptive if became the norm. It was said that business interests are not a sufficient basis to be heard. It was also emphasised that the default is a unitary trial and that, while these preliminary issues were fixed in LinkedIn this does not mean they are appropriate in Meta’s appeals: on the contrary, the hearing of second set of preliminary issues would warrant something exceptional.

44. He drew some contrast with test cases, noting they usually involve multiple cases with different facts, such as the cases arising from the Belfry investments, or the Bernie Madoff fraud. It was noted that such test cases need not necessarily be of binding precedential value but rather function as useful indicators.

45. It was said that the LinkedIn Appeal had already been set down for hearing and that there would therefore be a need to demonstrate compelling reasons why Meta needed to be heard. It was also said that there would need to be some “sample quality” to justify treating this case as a second pathfinder case which simply does not apply here.

46. It was pointed out on behalf of the Attorney General that the management of duplication would be exceedingly difficult and that Meta’s proposal was inevitably going to prolong and elongate the resolution of these issues, without any demonstration of how it would assist the Court. It was emphasised that Meta failed to show how the introduction of additional specific facts would assist the Court or even what those facts were, and that this very proposition is in tension with the acceptance that the issues are net legal questions.

Meta’s Reply

47. Meta’s counsel in reply pointed to the default rule being that each party should be able to progress their proceedings, subject to reasonable case management and that the DPC’s position is that none of the Meta appeals can progress, with LinkedIn being viewed by the DPC as a test case. It was said that this is the basis on which the analogy is drawn with test cases.

48. Reliance was placed on the decision in Avoncore Limited v. Leeson Motors Limited [2021] IEHC 163 (“Avoncore”) and on Kalix. It was said that Meta disputes that avoiding duplication is an overriding consideration and contends that duplication in terms of wasting court time

could be avoided by appropriate sequencing and case management to avoid repetitive submissions and heavy reliance was placed on Avoncore in that respect.

49. Meta also pointed to the importance of proportionality and fairness to both parties (opening Kalix and Avoncore in this proposition) and contended that the court must balance considerations of proportionality and fairness.

50. The application was said not to be excessively burdensome, as Meta is seeking leave to deliver submissions and to be heard, perhaps adding two days to the hearing, which was described as a low burden given the significance of the issues.

51. The distinguishing feature of this case, which warrants it being treated as the second pathfinder, was said to be the expert report of Mr Peters and it was said that the Court has to consider the types of evidence that may need to be adduced, the different factual permutations, and that this would inevitably be of assistance to the court.

52. It was said that the Court must balance considerations of fairness and proportionality, and that there is no rule that the first party to raise an issue of law necessarily is entitled to go forward ahead of all other cases pending at the same time.

53. In terms of the impact of the proposal on the other pending statutory appeals, counsel for Meta fairly accepted that Meta reserved its rights as to what, if any, further preliminary issues it may seek to advance in any of those cases, even if these four preliminary issues were heard and determined in its Passwords Appeal.

DECISION

54. The starting point, as acknowledged by all parties, is that the Court has a broad discretion in matters of case management, subject to the overriding imperative of ensuring the just and efficient use of the resources of parties and of the Court. In Kalix these points were emphasised and in Avoncore McDonald J. states,

“The court has a discretion to ensure that scarce court resources and the resources of parties to litigation are not inappropriately wasted by an unnecessary duplication of litigation.” (at [29(c)]

55. When it comes to the provisions invoked here, Order 25(1) and Order 34(2) of the Rules of the Superior Courts, these are necessarily overlaid with critical considerations of conservation of cost, time and convenience. In Campion v. South Tipperary County Council [2015] 1 IR 716 it was said that:

“Whatever may be the precise contours of either or both Order 25(1) and Order 34(2)

of RSC, it is clear that each has a common purpose namely, to save time and cost, when the preliminary process is compared with any other suggested method of hearing, including a full trial of the issues raised. ( Duffy v. News Group Newspapers Limited (No.2) [1994] 3 I.R. 63, and Croke v. Waterford Crystal Limited (Unreported, High Court, Smyth J., 26th June 2003). Convenience will also be a consideration and whilst there is no express reference to such in Order 25, as there in Order 34, r.2, nonetheless this matter has equal application to both rules.” (at [28])

56. Before considering how this undoubtedly broad discretion of the Court should be exercised in the context of Meta’s motion, I consider it necessary to be very clear about what this motion is not:

- It is not an application for the LinkedIn Appeal or this appeal to be designated as a pathfinder case for other statutory appeals.

- It is not a motion by the DPC to stay Meta’s proceedings.

- It is not a motion by Meta to be joined as a notice party or similar to the LinkedIn Appeal.

- It is not a motion for the cases to be linked, consolidated or managed together.

57. This application is one that seeks to have a list of four preliminary issues listed for hearing at the same time or directly after (and before the determination of) the same issues that are currently listed for hearing in the separate LinkedIn proceedings. It is a motion which has been described as unorthodox by the State and for which I certainly am aware of no precedent.

(a) Test for Preliminary Issues

58. The first important point is that hearing of a list of four identified preliminary issues has been fixed in the LinkedIn Appeal since 25 June 2025. These issues are to be heard by this court over three days commencing on 2 December 2025 and will be determined as net, discrete questions of law. It is inherent in the fact that they are being tried as preliminary issues, by way of deviation from the default unitary trial, that there are no contested issues of fact and that

the questions are not heavily fact dependent. The issues that have been so fixed for trial are and must necessarily be capable of being determined divorced from any factual controversy.

59. Following the hearing in December 2025, these preliminary questions of law will be determined by this court and will constitute the decision of the court on the net legal questions raised.

60. By this application, Meta is asking that it also be permitted to have precisely the same list of preliminary issues determined in its proceedings. It bases this application heavily on the proposition that there are aspects of its statutory appeal in the “Passwords” appeal that are relevant and would assist in the determination of the issues by providing an additional factual permutation.

61. The legal questions are going to be determined by the court and will not involve specific findings of fact. Given the purpose and scope of the rules on preliminary issues, it would take something quite exceptional for Meta to demonstrate that the factual matrix of its case is necessary for the court to properly decide the questions of law which have already been identified and fixed for hearing in the LinkedIn proceedings. I do not believe that this has been done.

62. The gravamen of Meta’s argument at the hearing is that the additional facts (specifically the expert report of Mr Peters) should be before the Court in determining the preliminary issues and that this will assist the Court in contextualising those issues.

63. As a general point, I see no basis to believe that there is a relevant or material difference of underlying facts in the two appeals for the purpose of the trial of the preliminary issues. While Ms Varian in her replying affidavit asserts that “the underlying factual matrix is different”, I have no information in that respect and see no justification for that assertion or how it is said to be relevant to the determination of the specific preliminary issues.

64. Turning to the specific question of the expert report, Ms Varian fairly accepts Meta “cannot take a position” as to whether the expert evidence proposed to be introduced by Meta does in fact overlap with the evidence proposed to be introduced in the LinkedIn Appeal. I have been given no basis to believe that there is not a suitable evidential foundation for the hearing of the preliminary issues, including issue 4, as directed by the Court order in LinkedIn. Each question of law must be a net, discrete one, and I am not convinced the court would need to see more than one specific report in a specific statutory appeal to be able to have a sufficient factual premise to decide a net question of law.

65. In any event, given the function of preliminary issues, the role of varying facts must necessarily be very limited, and it has not been shown to my satisfaction that there are any shortcomings with the LinkedIn proceedings as a factual premise for the preliminary issues such as could justify a second hearing of the same questions.

66. In an authority that was opened by the DPC, L.M. v The Commissioner of An Garda Síochána and others [2015] 2 IR 45 (“LM”) Donnell J. delivered the judgment of the Supreme Court and cautioned as follows,

“In my view, a court retains power to refuse to determine a preliminary issue if, after careful analysis, it becomes apparent that some aspect of the issue was heavily fact dependent, or that a possible outcome would be so contingent or qualified as to require almost a form of advisory opinion.” (at [34])

There is in fact no suggestion here that the preliminary issues are heavily fact dependent, nor should there be, or they would risk losing their character as preliminary issues.

67. Another theme that emerges from Meta’s submissions is that it would be unfair or unjust for these legal questions to be determined without a right being afforded to Meta to make submissions in respect of them. I fully accept and appreciate the importance of the preliminary issues raised for Meta. However, the purpose and function of preliminary issues must not be overlooked. The proposition that a finding on a net question of law, divorced from factual controversy, would be binding in other unrelated cases is a feature of our common law system and the operation of the doctrine of precedent - a point well - emphasised by the State in its submissions.

68. Indeed, In LM, O’Donnell J noted that one purpose and consequence of preliminary issues can be to act as precedents on importance legal questions for other cases (at [39]).

69. Similarly, the fixing of these issues in the LinkedIn Appeal for determination as net legal issues, has the inevitable consequence that their determination in those proceedings will have precedential weight for other statutory appeals. However, Meta has not identified any basis to conclude that those proceedings are not a suitable foundation for the trial of these preliminary issues and there is no suggestion that the issues themselves are not appropriate for preliminary determination – quite to the contrary.

70. There was some reference in the affidavits to Meta not being satisfied that “its position on the preliminary issues will be fully determined in the LinkedIn Proceedings” (Ms Varian’s second affidavit at [19]) but there is no right of a litigant to present its position on important questions of law that arose first in other proceedings. That is simply not a right that arises. The same

conclusion falls to be made on the point about Meta not having a right to appeal the decision of the Court on the preliminary issues in the LinkedIn appeal: that is a consequence of our system of administration of justice and the rules governing standing to appeal.

71. The overriding fact is that these questions of law have been identified, a court order has been made for their trial as such, and there is no evidence before me that they cannot properly or fairly be determined in the LinkedIn appeal. It has also not been shown to me why the interests of the efficient conduct of the proceedings or allocation of court time and resources favours the same issues being listed for determination again in separate proceedings.

(b) Pathfinder Cases

72. The second issue I want to address is that of so-called “pathfinder” cases. Meta relies quite heavily on the proposition that this is to be treated as pathfinder litigation for the purposes of the trial of the preliminary issues.

73. It is important that, while references have been made by all parties to the cases concerning “pathfinder” or “test cases”, nothing that is said now in the context of Meta’s appeal can convert what happened in the LinkedIn proceedings into anything other than a trial of preliminary issues. The order of the Court is clear: it was an order fixing the four issues identified for preliminary hearing. There is no reference to that case being a pathfinder for others (although its outcome will of course have an important legal precedential effect for ensuing cases).

74. I note the position of the DPC and the State that some analysis that appears in the pathfinder cases may be usefully adopted and provide guidance in this case. I can certainly see some sense to that approach, but I do not consider it appropriate or of assistance to carry the pathfinder analogy further than that.

75. The pathfinder model has been used in several cases where there is a multiplicity of overlapping litigation. There is a flexibility and informality to it, not being a practice that is governed by rules or legislation. However, there are some features of the pathfinder model which appear near universal, and which highlight why that model is not of material assistance or relevance here (I will return to the judgment in Xerico on which counsel for Meta relied below).

76. The judgment of Simons J in Lynch v. Minister for Health [2024] IEHC 712 at paras 9 and 10 is particularly useful in giving an overview of pathfinder models,

“It should be explained that the concept of a “test case” or “lead case” is essentially a case management tool rather than a characterisation for costs purposes. The concept is employed where there are a large number of cases which present the same or similar issues. The court will seek to select one of these cases as a pathfinder case. The hearing of the selected lead case will then be expedited, with the balance of the cases adjourned generally to await the outcome of the same. This is done in the expectation that the final judgment delivered in respect of the lead case will have precedential value in respect of the balance of the cases. The remaining cases can then be disposed of shortly.

If, for example, the applicant in the lead case has been unsuccessful, then it is likely that the other applicants will discontinue their cases.

The selection of a lead case is not an exact science. Depending on the legal points raised, it may even be necessary to select more than one case in order to ensure that an example of each of the various factual permutations arising in the pool of proceedings is represented. It may also be the position that the initial lead case will fall away and have to be replaced by another. This may be somewhere the applicant in the first case elects not to pursue an appeal.”

77. There are of course cases where there has been more than one pathfinder – Avoncore is an example which Meta invokes. That case involved an application to generally stay one claim for damages arising from the same incident pending the final determination of another case. I do not consider it to be properly comparable to this situation. Moreover, what was envisaged in that case was that the legal teams (who were common to both cases) would effectively manage the proceedings and each step in them to minimise overlaps, costs and duplication.

78. That case well-exemplifies the typical structure and effect of pathfinder litigation: the effect of which is that one/more cases progress all the way to conclusion, while others are stayed. It envisages a long-term impact on the proceedings, which are stayed in deference to a sample case proceeding.

79. This is not that situation. LinkedIn was not selected as a pathfinder. No comparison has been drawn with the facts of LinkedIn. It was simply first in time and raises important legal issues that will be important for other cases that follow. While it is the view of the DPC that the other statutory appeals should not progress until those preliminary issues are resolved, this is a view indicated in correspondence, it is not binding or determinative and I do not see that Meta in any event asserts prejudice or disputes the merit of awaiting the outcome of the preliminary issues (such opposition would indeed be difficult to reconcile with the premise of this motion).

80. It is also typical in pathfinder litigation, that there would be some consideration and assessment of the facts and issues common to multiple sets of proceedings (often numbering in the hundreds) and then a deliberate decision taken as to which of the cases is the most appropriate to bring forward to conclusion, while the others remain parked. The intention of that approach is that the final outcome of the pathfinder case or cases will influence the approach and possibly the outcome of the other cases. It may be that more than one case is advanced, owing to the specific factual permutations that arise, for example.

81. Again, this is not what has happened here. There is no proposal here that the Meta Appeals would be stayed until the final resolution of the LinkedIn Appeal and there was no discussion or decision about LinkedIn being a suitable case to represent the other pending statutory appeals. There has been no such analysis – either in the context of the LinkedIn Appeal or in the Meta Appeals. I have not been shown how the facts of either the LinkedIn or the Passwords Appeal are models for the other pending appeals, or why or how both of them engage facts which are materially different such as to necessitate a double pathfinder case.

82. Indeed, it is not clear to me that Meta is properly committed to the pathfinder model beyond wanting to be heard in relation to these preliminary issues. Meta does not make any concession or suggestion that the preliminary issues will decide the outcome of any other statutory appeals

– or even preclude applications for the trial of further preliminary issues. Rather Meta asserts in its submissions that it is reserving the right to raise further preliminary issues in other appeals.

83. Turning then to the case of Xerico v. Residential Tenancies Board which was helpfully opened by counsel for Meta. Xerico concerns the construction of the appeal provisions in the Residential Tenancies Act 2004, that provided for complaints to be made to the Residential Tenancies Board about landlord conduct following which the Board can then investigate and appoint an authorised officer to prepare a draft investigation report, for which submissions can be sought from the landlord. A final investigative report is then sent that to the Board after which there can then be an oral hearing, further submissions sought, or a final decision made.

A right of appeal ensues.

84. In Xerico, the Board had upheld complaints that the landlord had unlawfully increased the rent contrary to rent pressure zone provisions, and twenty appeals were brought by the same appellant. The Circuit Court directed that two preliminary issues of law concerning the scope of the appellate jurisdiction be tried. It was said by Meta that this showed the importance of

having two cases to exemplify different facts in an appeal mechanism which is akin to that in the 2018 Act.

85. Some important points which occurred to me from reviewing Xerico is that it is of course an example of pathfinder cases being used for the trial of preliminary issues and it is the only example of that of which I am aware. However, I am not certain that any further guidance can be derived from the case. In particular there is no indication about why or how the pathfinder cases were selected and there is no particular analysis of that issue in the judgment. It is also important to note that the pathfinder cases and the cases for which they were pathfinders were brought by the same appellant, with the same legal team, making the same arguments and indeed the judgment just refers to the “appellant” and the case seems to have been treated as one appeal. It is also of note that the judgment of the Court of Appeal places no particular emphasis on the distinct facts of these two cases or any indication as to why two pathfinder cases were selected. So, while I understand why Meta relies on this judgment, I consider it to be of limited assistance to the issue raised here.

86. To summarise, while I have benefitted from the very able submissions of all of the parties I am not persuaded that the pathfinder analysis is apt here. The same underlying considerations of judicial economy and efficiency are of course important in determining how to fairly and justly manage litigation in a legal system with finite resources, but pathfinder cases are quite distinct to the issue here, which concerns – and must be tightly limited to – the trial of preliminary issues of law. There was no decision to identify and bring forward LinkedIn as a pathfinder.

87. Moreover, even if the pathfinder analysis could apply here, I have not been shown why a second pathfinder is necessary: Meta has not contrasted or compared the facts of the Password Appeal and those of the LinkedIn Appeal (other than referring to the expert report in the Password Appeal). There is no demonstration of the differences or similarities between the Passwords Appeal and the LinkedIn Appeal, or between either of those appeals and the other cases for which they are asserted to be pathfinders. I have no factual basis for correlating or contrasting the facts of any cases so as to decide whether and how many pathfinders would be appropriate.

(c) Case management considerations

88. In terms of whether case management directions could nonetheless be made to allow for the combined or sequential hearing of the same preliminary issues in the two appeals, the point most heavily emphasised by DPC was the need for case management to ensure efficiency and cost effectiveness and reduce the risk of duplication.

89. Meta’s counsel points out that duplication can be avoided through case management, asserting that it could be mitigated by sequencing and directions to avoid duplication, with reliance being placed particularly on the judgment in Avoncore.

90. It can well be understood how duplication could be avoided in Avoncore when two full trials of liability arising from the same facts were going forward in tandem: the same legal teams were acting in both cases and could divide the witnesses, the expert reports, the questions of law they would each address to ensure that the same terrain was not covered twice.

91. However, it has not been explained to me, and I confess I fail to understand how a court could effectively sequence and manage the hearing in two cases involving four different legal teams (plus the State in each) of the same legal questions in any way that could conceivably avoid duplication given that the purpose of Meta’s application is to be heard on the same legal issues that are already listed for hearing in LinkedIn.

92. I have given this some thought but simply cannot see how it would result in anything other than the court receiving perhaps six different sets of written and oral submissions addressing the same legal questions, but perhaps with differences of nuance and emphasis and different authorities relied upon, and not necessarily intersecting across the two cases. This risk is confirmed by the affidavits of Ms Varian which indicate Meta’s interest in having different versions of the same legal issues presented.

93. I have listened to the concerns of proportionality and fairness raised by Meta and I do understand and have carefully weighed the importance of the questions and Meta’s desire to be heard in relation to them. However, I have to manage these proceedings in a manner that is workable within the scope of the court’s discretion and the Rules of the Superior Courts.

94. The overarching imperative when it comes to Order 25(1) and Order 34(2) is to consider how best to conserve costs, time and achieve efficiency in the conduct of litigation.

95. The issues are listed for hearing in the LinkedIn Appeal. I see and have been given no reason to apprehend that the issues will not be fully and comprehensively argued and presented to the court in that appeal. There are some assertions by Ms Varian that the arguments that Meta would advance on the legal questions “might well be different” to those advanced in the LinkedIn proceedings, but that is not a consideration that I would regard as weighing in favour of the orders sought.

96. On the contrary, I would apprehend that allowing the same issues to be argued close in time in two separate appeals by different legal teams in front of the same Judge with different arguments and approaches in each, could give rise to a very heavy and difficult burden on the Court, in trying to disentangle, reconcile and separately determine the same identical issues in two separate cases. I do not see that placing heavy reliance on facts (as Meta appears to envisage) would assist, and on the contrary, it could lead to a more complicated task for the Court in ensuring that the issues retain their character as discrete net questions of law.

97. In short, no sufficient justification has been given to warrant the imposition of the proposed and substantial burden on the Court. It would also of course be onerous and demanding for the DPC and the State to deal with two different sets of submissions on the same issues in two cases. The default is that issues of law are determined in the first case in time and are binding in subsequent cases. That must be the default here. The Passwords Appeal is second in time to LinkedIn’s appeal and thus, the issues will be decided in the latter.

(d) Delay

98. One final point which I wanted to address for the purpose of completeness is the issue of delay which was raised by the DPC.

99. I do not regard the delay as prohibiting a motion for the trial of preliminary issues. However, the chronology in Ms Varian’s replying affidavit highlights a point of some importance which is that there was no reference to steps taken between the issue of the Passwords Appeal on the 23rd of October 2024 and the next step taken in that chronology on the 25th of July 2025. By contrast, by that latter date, the trial of the preliminary issues in the LinkedIn proceedings had been assigned a hearing date and directions for that hearing had been put in place.

100. The delay is not something I regard as a bar to Meta’s application for the hearing of preliminary issues, and I accept Meta’s position in that respect, but it does have the important and inescapable consequence that the status quo as of the date when Meta issued this Motion on 3 October 2025 -almost a year after the issue of the Appeal - was that there had been significant developments in LinkedIn and those proceedings were already in a state of readiness such that they had already been case managed to ensure the speedy hearing and efficient resolution of key legal questions. Meta cannot assert that any injustice arises from this circumstance.

CONCLUSION

101. For the reasons given in this ruling, I do not consider that it is appropriate or consistent with the interests of justice or the efficient and just conduct of these proceedings to grant the relief sought by the Motion.

102. The orders sought are therefore refused.