In the matter of an application by the Secretary of State for Northern Ireland for Judicial Review

A decision applying public interest immunity is an application of substantive evidential law, not an exercise of discretion. An appellate or reviewing court must decide for itself whether the first-instance decision was right and where the overall public interest lies.

When national security is relied upon, the court must accept the responsible Secretary of State’s assessment of the existence and extent of the risk unless it is unsupported by evidence or is Wednesbury irrational. The court must then independently balance that risk against the public interest served by admitting the evidence or a gist. Before ordering disclosure, it must obtain sufficient information from the responsible authority and assess the gist’s practical contribution to the proceedings.

A coroner upheld ministerial claims of public interest immunity over documents relevant to an inquest into a Troubles-related killing, but directed disclosure of two alternative gists of information. The Secretary of State maintained that disclosure would compromise the policy of neither confirming nor denying the involvement of informers and create a real risk of serious harm to national security.

Humphreys J dismissed challenges concerning gist 1 in [2024] NIKB 18 and gist 2 in [2024] NIKB 32. A majority of the Court of Appeal dismissed the appeal in [2024] NICA 39; McCloskey LJ dissented in [2024] NICA 82.

The Supreme Court considered the standard governing judicial review of a public interest immunity decision, the treatment of ministerial national-security assessments, and the balance between national security and the contribution which the gists could make to an inquest that could no longer be completed.

1. Appeal allowed unanimously. Lord Sales and Lord Stephens delivered the judgment, with which Lord Reed, Lord Hodge and Lord Lloyd-Jones agreed. Neither gist was to be disclosed.

2. Public interest immunity determines whether relevant evidence is inadmissible as a matter of substantive evidential law. It does not confer a discretion on the first-instance decision-maker. An appellate or reviewing court must therefore decide whether the rule was correctly applied and must form its own view of the Wiley balance. The High Court and Court of Appeal majority erred by applying only ordinary supervisory review and by affording the Coroner a wide margin of discretion.

3. The court retains responsibility for deciding where the overall public interest lies. It must, however, accept the responsible public authority’s assessment of the existence and extent of a national-security risk unless that assessment lacks evidential support or is Wednesbury irrational. The formulation in Litvinenko that a ministerial assessment should be accepted unless there are “cogent or solid reasons” to reject it was capable of misleading. A court rejecting such an assessment must explain its reasons.

4. The Coroner neither found the Minister’s assessment unsupported nor found it irrational. She therefore had to proceed on the basis that disclosure created a real risk of serious harm to national security. Her conclusions that the gists removed or mitigated that risk, and her alternative balance based on only limited harm, were legally erroneous.

5. The Coroner also failed to obtain the reasoned views of the Minister or Secretary of State before deciding upon either gist. Given the national-security context, she was obliged to inform herself fully. The Secretary of State, rather than the Chief Constable, was the authority asserting the immunity claim and was ordinarily best placed to provide the overall national-security assessment.

6. The statutory deadline preventing completion of the inquest was a material consideration. It greatly reduced the public interest served by admitting the gists. Their abstract and indeterminate content could make no more than a negligible contribution to findings or further investigation and risked encouraging speculation. Applying the Wiley balance itself, the Supreme Court held that the public interest was clearly against disclosure.

1. United Kingdom Supreme Court: Allowed the appeal unanimously and held that neither gist should be disclosed: [2025] UKSC 47 .
2. Court of Appeal in Northern Ireland: By a majority, dismissed the Secretary of State’s appeal: [2024] NICA 39. McCloskey LJ dissented: [2024] NICA 82.
3. High Court of Justice in Northern Ireland: Humphreys J dismissed the challenges concerning gist 1 in [2024] NIKB 18 and gist 2 in [2024] NIKB 32.
4. Coroner: Upheld the public interest immunity claims over the underlying documents but directed disclosure first of gist 1 and subsequently of gist 2.