Fair and Equitable Costs Allocation in Modularized Environmental Proceedings: Doyle & Ors v An Bord Pleanála [No.2]

Introduction

The High Court’s decision in Doyle & Ors v An Bord Pleanála & Ors [No.2] ([2025] IEHC 205) addresses how costs should be allocated in modular judicial review proceedings under the Planning and Development Act 2000 (as amended) and the Climate Action and Low Carbon Development Act 2015. The applicants—Colin Doyle, Friends of the Irish Environment CLG, Futureproof Clare, Martin Knox and Christine Sharp—challenged a data-centre planning permission granted by An Bord Pleanála. After Module I (sub-grounds 91–93) was conceded by the Board and dismissed by the Court, the parties returned on mention to determine whether the applicants should recover costs of the losing module. The central issues were:

The interaction between modularization and costs orders;
The impact of the Aarhus Convention’s “fair, equitable and not prohibitively expensive” requirement on costs;
The fairness of making “no order as to costs” for unsuccessful points and reserving the developer’s costs.

Summary of the Judgment

Humphreys J. refused to disturb his provisional costs order following Module I. The key outcomes were:

The applicants’ costs of Module I remain on the basis of “no order” (they receive nothing for the points they lost).
The notice party’s (the developer’s) costs in relation to the costs-variation application are reserved, to be dealt with by way of set-off later if appropriate.
The provisional order will not be perfected until the entire multi-module proceeding concludes.

The Court held that modularization does not entitle a losing party to costs merely because the points were heard in a separate module, and that neither domestic law nor the Aarhus Convention requires winners (including private developers) to pay the costs of losing environmental applicants.

Analysis

Precedents Cited

The judgment draws on several authorities:

Doyle v An Bord Pleanála (No.1) [2025] IEHC 158 (Unreported) – the first module’s merits and provisional costs order.
G.T. v Minister for Justice [2025] IEHC 207 – noted by Phelan J. on the chilling effect of adverse costs orders in unmeritorious environmental claims.
Order 99 RSC (Rules of the Superior Courts) – particularly r. 2(3) on awarding costs “as it goes along” and r. 6 on set-off of costs.
English Civil Procedure Rules, r. 46.27 – defining “prohibitively expensive” in Aarhus-compliant UK practice.
The Aarhus Convention, arts. 9(2)–(4), and Compliance Committee reports – clarifying that proceedings must be fair, equitable and not prohibitively expensive, but imposing no positive obligation on winners to pay losers’ fees.

These authorities underpin the Court’s view that costs must reflect the merits of each module, that modular hearings proceed on defined assumptions, and that the negative prohibition on “prohibitively expensive” costs in Aarhus does not translate into an entitlement for wholly unsuccessful applicants to full or even partial costs.

Legal Reasoning

The Court’s reasoning can be broken down as follows:

Modularization and Costs Are Distinct: Modular hearings are ordered for efficiency, to contain challenges to specific issues (e.g., a conceded point). Their existence does not in itself alter the fundamental rule that the loser pays nothing.
Hypothetical Unitary Trial: Even without modularization, the applicants would either (a) lose entirely (and get no costs) or (b) win some points (and obtain costs limited to those points). They are no worse off by having Module I heard separately.
Aarhus Convention Interpretation: Article 9(4) requires fair, equitable, timely and not prohibitively expensive proceedings, but it does not oblige winning parties to cover the losing party’s costs. The Convention’s “negative” obligation prohibits excessive costs, not the imposition of any costs order against an applicant who loses some points.
Fairness and Certainty: A rule that losers get no costs is clear and certain. Reserving costs for winners only where they prevail avoids “bogus” entitlements and windfall costs awards.
Set-Off Mechanism: Where an applicant prevails on some grounds but loses on others, the Court can set-off the costs of losing points against those awarded for successful points—again ensuring no free lunch for protected applicants.

Impact

This decision establishes several important guiding principles:

Costs Discipline in Modular Proceedings: Courts will scrutinize each module on its merits and award costs only for successful points.
Clarity for Practitioners: Applicants cannot assume that modularization guarantees costs recovery. They must assess whether each module is worth pursuing financially.
Policy Balance: While environmental justice remains a public good, private developers and public bodies must not be overburdened by costs for points that applicants lose.
Aarhus Compliance: Irish courts align with international practice in interpreting the Convention as prohibiting “prohibitively expensive” costs but not requiring winners to pay losers.

Complex Concepts Simplified

Modularization: Breaking a single judicial review into separate modules on discrete grounds to promote efficiency and focus.
No Order as to Costs: The default outcome when a party loses—no costs are awarded for that part of the proceeding.
Set-Off: Offsetting costs awarded for successful grounds against costs incurred in unsuccessful grounds, resulting in a net figure.
Aarhus Convention Art. 9(4): Requires proceedings to be fair, equitable and not prohibitively expensive, but imposes no positive duty on winning parties to pay losers’ fees.
Prohibitively Expensive: Costs so high that they exceed a claimant’s resources or are unreasonable in context (per CPR r. 46.27).

Conclusion

Doyle & Ors v An Bord Pleanála [No.2] clarifies that in modularized environmental judicial reviews:

Applicants who lose on a module receive no costs for that module, irrespective of its separation.
Winners’ costs are reserved where further discussion (e.g., set-off) may be required once all modules conclude.
The Aarhus Convention’s cost provisions are negative—protecting against excessive costs but not creating a right for winners to cover losers’ fees.

This judgment offers a coherent framework balancing access to environmental justice with cost discipline, ensuring that parties proceed pragmatically and bear financial consequences for canvassing unmeritorious points.