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

The correctness standard of review does not apply automatically whenever a scheme uses the term “child”. The applicable standard depends on the statutory or policy context and the division of responsibility it establishes. The Court determines the meaning of “child” as a matter of law, but application of that criterion by the primary decision-maker is generally reviewed for reasonableness. In the UK-France Treaty 2025 scheme, the Secretary of State’s decision to treat an unaccompanied person as an adult for inadmissibility and removal purposes was therefore subject to review for reasonableness, not correctness. The statutory rules governing removal detention, local-authority age assessments and judicial findings on age did not alter that conclusion. Different, legally distinct decisions concerning the same person may attract different standards of review.

The claimant, an unaccompanied asylum-seeker, challenged the lawfulness of proposed removal to France under the UK-France Treaty 2025. The Secretary of State had treated him as an adult and had made an inadmissibility decision and removal arrangements. The parties agreed that an unlawful decision to treat an unaccompanied child as an adult could make the removal unlawful.

The preliminary issue was whether judicial review of the Secretary of State’s age-related decision for inadmissibility and removal purposes applied a correctness standard, involving a substituted judicial determination of age, or the ordinary reasonableness standard. The claimant relied on statutory provisions, Home Office policy, linked detention and age-assessment decisions, and the Treaty’s exclusion of unaccompanied children.

1. Preliminary issue determined. The Secretary of State’s decision to treat an unaccompanied person as an adult for the purposes of inadmissibility certification and removal under the UK-France Treaty 2025 was subject to the reasonableness standard of review. The correctness standard did not apply.
2. The Court determines the legally correct meaning of an instrument, including policy guidance. Application of the instrument to the facts is ordinarily an evaluative matter for the primary decision-maker, reviewed for reasonableness. The word “child” does not invariably attract correctness review. A (Croydon) and AA (Sudan) concerned particular statutory schemes whose language and structure assigned the relevant age question to the Court. They did not establish a universal rule.
3. The statutory restrictions concerning unaccompanied children in detention for removal, including Immigration Act 1971 Sch 2 para 18B and Immigration and Asylum Act 1999 s 10(9)(f), did not create an equivalent correctness requirement for the separate powers to declare a claim inadmissible or to remove. Those powers contained no corresponding statutory restriction.
4. The Home Office policy documents identified “child” as a criterion for decision-makers to apply. Their references to local-authority or NAAB assessments, review, and the binding effect of a judicial finding did not require the Secretary of State to suspend inadmissibility or removal proceedings until all possible age litigation had finally concluded. The policy guidance did not establish a correctness-based division of responsibility.
5. A local-authority age assessment was a mandatory legally relevant consideration under Part 4 of the Nationality and Borders Act 2022. It was not, by the statutory scheme, a prerequisite whose legality automatically determined the legality of the Secretary of State’s later inadmissibility or removal decision. The reasoning concerning unlawful prior decisions in DN (Rwanda) did not operate in reverse.
6. Although removal and detention for removal were closely connected, unlawful detention did not automatically vitiate the removal decision. Different linked decisions could attract different standards of review. A successful challenge to detention or to a local-authority assessment could nevertheless require the Secretary of State to reconsider the continuing inadmissibility and removal decisions.
7. The Treaty was an undomesticated international agreement without direct effect. Its terms could not themselves support a direct judicial-review claim. The Judge nevertheless expressed reluctance to treat it as wholly irrelevant to public law questions, including the legality of relying on policy or maintaining an age conclusion.
8. Questions concerning the closeness of reasonableness review, fresh evidence, collateral challenge to Merton compliance, and the precise age criterion remained for the subsequent hearing. Consequential matters, including permission to appeal, were deferred.