“Costs in the Cause” Is an “Award of Costs” Under Order 99, Rule 2(3): Clarifying the Distinction from Reserved Costs on Interlocutory Motions
1) Introduction
This judgment concerns the allocation of costs arising from an interlocutory motion brought by Meta Platforms Ireland Limited (“Meta”) against the Data Protection Commission (“the DPC”). The motion sought directions for the trial of preliminary issues and, crucially, an order aligning the hearing of those issues with (or immediately after) the hearing of the same issues in separate proceedings involving LinkedIn and the DPC (“the LinkedIn Proceedings”). The substantive relief sought by Meta on that motion was refused by ex tempore judgment: Meta Platforms Ireland Limited v. Data Protection Commissioner [2025] IEHC 631.
The present decision addresses three interlinked questions:
- Timing: whether the costs of the motion should be determined now or deferred.
- Meaning under Order 99: whether an order that costs be “costs in the cause” constitutes an “award of costs” for the purposes of Order 99, Rule 2(3) of the Rules of the Superior Courts.
- Allocation: whether the DPC, as the entirely successful party on the motion, should receive its costs, or whether costs should be “in the cause”.
2) Summary of the Judgment
Cahill J held that:
- The motion was finally determined, and therefore its costs fall to be decided now (not postponed on the basis that further preliminary issues might arise later).
- “Costs in the cause” is an “award of costs” within the meaning of Order 99, Rule 2(3). It is distinct from “reserving” costs (which defers adjudication and is only permissible where it is not possible justly to adjudicate upon liability for costs).
- The appropriate costs order was “costs in the cause”, notwithstanding the DPC’s success, because the motion—while unsuccessful—was not unreasonable, served a useful purpose in ventilating important procedural/structural issues, and the parties engaged constructively.
- No order was made regarding costs incurred by the State (which was not strictly a party but analogous to a notice party).
3) Analysis
3.1 Precedents Cited
The judgment is a costs decision, but it makes a significant clarificatory contribution by synthesising the costs jurisprudence around Order 99, Rule 2(3), the Legal Services Regulation Act 2015, and case-management practice. The principal authorities and their influence are as follows.
(a) Daly v. Ardstone Capital Limited [2020] IEHC 345
Cahill J relied on Murray J’s structured summary of how the court should approach costs on interlocutory applications: the general discretion is preserved; the court should (unless it cannot justly do so) make an order for costs upon disposition of an interlocutory application; the court must “have regard to” the factors in s.169(1) of the 2015 Act; and where a party is “entirely successful” the court should “lean towards ordering costs to follow the event”, subject to the statutory factors. This provided the backbone of the analytical framework applied at paragraphs 46–58.
(b) Pembroke Equity Partners Limited v. Corrigan [2022] IECA 142
From Pembroke, the court drew the proposition that, in interlocutory applications, there is a broad presumption (only a presumption) that an “entirely successful” party should receive its costs. The emphasis on “presumption—not rule” is important: it underpinned the court’s willingness to depart from “costs follow the event” once the s.169(1) considerations were weighed.
(c) Haughey v. Synnott [2012] IEHC 403
Haughey (Laffoy J) was central to the interpretive question about Order 99, Rule 2(3)’s predecessor and the distinction between:
- reserving costs (deferring adjudication, permissible only where it is not possible justly to adjudicate at that stage), and
- costs in the cause (a species of costs adjudication, not a deferral).
Cahill J adopted Laffoy J’s reliance on Delany & McGrath on Civil Procedure which expressly treats “costs in the cause” as one of the available orders a court may make when adjudicating costs of an interlocutory application—contrasted with reserving costs.
(d) Irish Coursing Club v. The Minister for Health [2021] IEHC 157
The DPC invoked Irish Coursing for the proposition that treating costs as “costs in the cause” engages the “not possible justly” threshold in Order 99, Rule 2(3). Cahill J distinguished its value: the judgment suggested terminology confusion and, critically, did not address (through adversarial debate) whether “costs in the cause” is conceptually the same as reserving costs. The High Court therefore did not treat Irish Coursing as resolving the interpretive question.
(e) ACC Bank plc v. Hanrahan [2014] 1 IR 1
Clarke J’s discussion of the purpose behind the interlocutory costs rule—discouraging unreasonable motions or unreasonable opposition—was used to reinforce that Order 99, Rule 2(3) is not merely procedural housekeeping but a policy lever. Importantly, Clarke J’s express contrast between “costs in the cause” and “reservation of the costs” supported Cahill J’s conclusion that “costs in the cause” is an adjudication (an “award”) rather than a deferral.
(f) Cork Plastics (Manufacturing) v. Ineos Compounds U.K. Ltd. [2011] 1 IR 492
This authority was used to address the practice in complex litigation and case management: Clarke J indicated that costs associated with orderly case management are often “costs in the cause” where parties constructively engage, whereas discrete contested issues requiring a formal judgment might justify individual costs orders. Cahill J treated this not as a rigid rule, but as a sensible practice direction: fully contested case-management motions do not carry an automatic entitlement to “costs in the cause,” nor an automatic entitlement to “costs follow the event.”
(g) Avoncore Limited v. Leeson Motors Limited [2021] IEHC 163
Meta relied on Avoncore as an example where a refused application nonetheless led to “costs in the cause” because it served a useful purpose—debating issues and enabling directions. Cahill J accepted the broader principle: usefulness is not limited to formal directions; a motion may justify “costs in the cause” where it appropriately ventilates important matters and contributes to procedural clarity, even if it fails.
(h) Meta Platforms Ireland Limited v. Data Protection Commissioner [2025] IEHC 631
Although the costs judgment is separate, Cahill J anchored the “finality” point in the earlier refusal decision, rejecting the idea that the motion remained “live.” She also referenced findings in that judgment that the LinkedIn preliminary-issue determination would have “precedential weight” for other statutory appeals, and that there was no justification for having the same issues determined again—supporting the conclusion that the interlocutory step had ended and its costs could and should now be allocated.
3.2 Legal Reasoning
(i) Determining costs now: interlocutory finality and procedural economy
The court first determined that the motion was conclusively disposed of: Meta’s specific request for preliminary issues to be tried in tandem with (or immediately after) the LinkedIn Proceedings was refused. The possibility of future, different preliminary issues did not keep this motion alive. As a result, there was no procedural unfairness in deciding costs now; indeed, Order 99, Rule 2(3) points in the opposite direction—costs should ordinarily be adjudicated upon disposition of interlocutory applications.
(ii) The key clarification: “costs in the cause” as an “award of costs” under Order 99, Rule 2(3)
The most precedent-significant portion of the judgment is the court’s resolution of the uncertainty identified by the DPC: whether “costs in the cause” counts as an “award of costs” (and therefore satisfies Order 99, Rule 2(3)’s requirement to “make an award of costs” upon determining an interlocutory application).
Cahill J offered two core reasons:
- Functional finality: the “not possible justly” test is about whether the court can decide liability now. “Costs in the cause” does not defer liability determination to the trial judge; it determines it by linking liability to the outcome of the main proceedings. Hence, it is an adjudication that leaves no residual costs task for the trial judge in respect of that motion.
- Authority and commentary support: Haughey (and Delany & McGrath) treat “costs in the cause” as a costs order available on interlocutory disposition, while ACC Bank plc v. Hanrahan linguistically and conceptually differentiates it from “reservation.”
This clarification matters because it prevents Order 99, Rule 2(3) from being misunderstood as forcing courts into a binary choice of either (a) “costs follow the event” now, or (b) reserving costs only where “not possible justly.” Cahill J confirms a third category: “costs in the cause” is a legitimate present adjudication which does not require meeting the “not possible justly” threshold.
(iii) Applying s.169(1) (Legal Services Regulation Act 2015) to a case-management motion
Having accepted that the DPC was “entirely successful” (engaging the presumption recognised in Daly and Pembroke), the court then weighed the s.169(1) considerations as adapted to interlocutory context:
- conduct of the parties;
- reasonableness in bringing/defending the motion;
- manner in which it was conducted;
- constructive engagement (drawing from Cork Plastics).
The court found the motion, though novel and unsuccessful, was not unreasonable given the magnitude of the issues for Meta across multiple pending appeals; it also produced procedural value by ventilating and confirming practical positions (including an agreed pause in steps pending the LinkedIn preliminary issues). Those considerations justified departing from “costs follow the event” and making costs “in the cause.”
3.3 Impact
(a) Clarified taxonomy for interlocutory costs orders
The judgment is likely to be cited where parties argue that “costs in the cause” is tantamount to reserving costs and therefore must satisfy Order 99, Rule 2(3)’s “not possible justly” threshold. Cahill J’s reasoning provides a clean doctrinal separation:
- Reserved costs: defers adjudication; only if not possible justly to decide now.
- Costs in the cause: a present adjudication that ties liability to the outcome; does not require “not possible justly.”
(b) Practical consequences for case management and complex litigation
The decision reinforces that courts retain flexibility to encourage constructive case management: even where a respondent “wins” a case-management motion, costs may still be placed “in the cause” where the motion was reasonably brought, useful, and conducted properly. This is particularly relevant in multi-proceeding regulatory litigation, where procedural coordination can be rational (even if not ultimately granted) and where cost sanctions could chill legitimate procedural applications.
(c) Interplay with s.169(1): “presumption” not “rule” on interlocutory success
The judgment exemplifies how s.169(1)’s “entirely successful” principle operates in practice on interlocutory motions: it sets a starting presumption but remains subject to context-specific factors—especially reasonableness and conduct.
4) Complex Concepts Simplified
- Interlocutory application: a step taken during a case (before final trial) seeking procedural or interim relief (here, directions about preliminary issues and scheduling).
- Costs follow the event: the usual idea that the winner gets their legal costs from the loser; under s.169(1) it is framed as an entitlement for the entirely successful party unless the court orders otherwise.
- “Costs in the cause”: the costs of the motion are not paid immediately by the losing party; instead, whoever wins the main case at the end recovers those motion costs. It is still a present costs decision—just one that defers which party ultimately pays to the outcome of the main proceedings.
- Reserved costs: the court makes no decision yet on who should bear the costs of the motion; it leaves the decision to a later stage (typically trial). Under Order 99, Rule 2(3), this is only permissible where it is not possible justly to decide liability at the interlocutory stage.
- Case management motion: an application aimed at organising and efficiently progressing litigation (timetables, sequencing issues, preliminary issues). Courts often avoid punitive costs outcomes on such motions where parties engage constructively.
5) Conclusion
Meta Platform Ireland Ltd v The Data Protection Commission [2026] IEHC 8 makes two notable contributions to Irish costs jurisprudence in interlocutory contexts. First, it confirms that an order directing “costs in the cause” is an “award of costs” for the purposes of Order 99, Rule 2(3), and is conceptually distinct from “reserving” costs (which is tightly confined by the “not possible justly” test). Second, it illustrates a pragmatic application of s.169(1) of the Legal Services Regulation Act 2015 to case-management motions: even where one party is entirely successful, costs may properly be placed “in the cause” where the motion was reasonably brought, procedurally useful, and conducted with constructive engagement.
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