Royal Mint Court Residents’ Association, R (on the application of) v Secretary of State for Housing, Communities and Local Government & Ors

For Aarhus costs protection, a judicial review must challenge a decision, act or omission alleged to contravene a provision of national law relating to the environment. It is insufficient that the decision is connected with environmental effects, or that its consequences may be addressed under an environmental or planning regime. The court must examine the wording, context and purpose of the legal provision under which the defendant acted. A decision taken under national-security powers does not fall within Article 9(3) merely because it may affect planning matters or the environment. A 14-day response period under the Pre-Action Protocol is a general expectation, not a rule of law. Amendments are not necessarily attributable to delay where the claimant could have raised the points in a reply and the amendments do not materially alter the grounds.

The claimant, a residents’ association, brought two related claims concerning planning permission for a proposed embassy at Royal Mint Court: a statutory challenge under section 288 of the Town and Country Planning Act 1990, and judicial review of national-security mitigation measures authorised by the Secretary of State for the Home Department.

At a case-management hearing, the court considered whether the judicial review attracted Aarhus costs protection under CPR rule 46.24 and whether the Secretary of State for Housing, Communities and Local Government should pay the claimant’s costs of amending the statutory challenge. Costs protection for the statutory challenge was agreed. The central issues were whether the judicial review fell within Article 9(3) of the Aarhus Convention and whether delay in responding to the pre-action letter justified a costs order.

1. Aarhus costs protection. The judicial review did not fall within CPR rule 46.24(2)(a). Applying HM Treasury v Global Feedback [2025] EWCA Civ 624, the relevant question was whether the challenged decision contravened national law relating to the environment. It was insufficient that the claim related to the environment, had environmental consequences, or concerned matters connected with environmental protection.

2. The Secretary of State for the Home Department’s decision concerned support for or imposition of mitigation measures under powers related to national security. National-security powers were both the focus of the decision and the source of the powers. The claim did not allege that the decision itself contravened a national law for the protection of the environment.

3. The asserted connection with the Community Infrastructure Levy regime and the planning legislation did not alter that conclusion. The alleged effects on decisions under the Community Infrastructure Levy Regulations 2010 and the Town and Country Planning Act 1990 were one step removed from the relevant environmental provisions. The judicial review therefore attracted no Aarhus costs protection.

4. Amendment costs. The application for the Secretary of State for Housing, Communities and Local Government to pay the costs of amendment was dismissed on the merits. The claim was complex and sensitive, the 22-page pre-action letter included extensive and sensitive disclosure requests, and the defendant responded within 16 days after explaining that 14 days was impracticable. The 14-day period was a general expectation rather than a legal rule.

5. The amendments could have been raised in a reply. They did not materially change the substantive grounds or add a new ground. Costs were therefore ordered to be in the case.