AH, R (on the application of) v Secretary of State for the Home Department

A court may supplement its judgment under its inherent jurisdiction where the consequential declarations are unclear or insufficiently recorded, even if the circumstances do not fall within the slip rule. The slip rule is directed to accidental errors, omissions or ambiguity in the judgment or order. It does not ordinarily address an intentional decision to leave the terms of consequential relief to be agreed after judgment. Where the court’s substantive conclusions are clear, a supplemental judgment may record the declarations necessary to remove uncertainty without altering the decision.

This was a supplemental judgment in two conjoined judicial review claims brought by AH and IS against the Secretary of State for the Home Department. The principal judgment was [2025] EWHC 3269 (Admin). The defendant sought, under Part 40.12, to supplement or revise the published judgment by setting out declarations arising from the court’s conclusions on the systems ground.

The claimants were neutral on the application. The central issue was whether the omission of the declaration terms fell within the slip rule or should instead be addressed through the court’s inherent jurisdiction.

1. Procedural route. The defendant’s application under Part 40.12 was doubtful because there had been no accidental error or omission. The court had intentionally invited the parties to agree the consequential order, and there was no ambiguity in the judgment itself.
2. Inherent jurisdiction. The safer course was to exercise the court’s inherent jurisdiction by issuing a supplemental judgment. This clarified the terms of relief without changing the substantive conclusions or the agreed order.
3. Declarations. For both claimants, the court recorded that, between 28 July 2023 and 11 March 2024, the defendant failed, in breach of Article 3 ECHR, effectively to implement the system at Brook House IRC so that immigration detainees within rule 35 of the Detention Centre Rules 2001 were protected from Article 3 violations.
4. The court further recorded that the defendant’s failure to identify the claimants as adults at risk in detention, release them on that basis, and avoid their mistreatment in detention resulted from the Article 3 systems breach. The supplemental judgment therefore clarified the declarations flowing from the principal judgment.

The judgment was supplemental to the High Court’s principal judgment in the same proceedings, reported at [2025] EWHC 3269 (Admin). No appellate decision was stated.