In the matter of an application by the Secretary of State for Northern Ireland for Judicial Review [2025] UKSC 47. Judgment 17 December 2025 here
More than 20 years ago 25-year-old Liam Thompson was shot and killed near a gap in a peace line separating nationalist and unionist neighbourhoods in Belfast. No one has ever been held accountable for his murder. Indeed, in the context of what the Supreme Court describe as “egregious and profoundly disturbing delays” there has still not been an effective and Article 2 compliant investigation into Mr Thompson’s death.
The abortive inquest that was commenced in 2023 has, however, given the Supreme Court cause to answer an important question of principle: What test, and what level of scrutiny, should be applied by a court reviewing a decision to disclose material over which a claim of Public Interest Immunity (‘PII’) has been made?
In a unanimous judgment, overturning the decisions of the Coroner, a High Court Judge, and two Court of Appeal judges, the Supreme Court affirms that the question whether evidence is covered by PII is a substantive question of the law of evidence, not an exercise of judicial discretion. A first instance court must determine where the overall public interest lies, by conducting the balancing exercise set out in R v Chief Constable of West Midlands Police, Ex p Wiley [1995] 1 AC 274. The inquisitorial nature of an inquest will raise the stakes in PII cases as compared to civil litigation. If the first instance court misidentifies the public interest, it has gone wrong in law and an appellate or reviewing court is required to consider the balancing exercise itself and correct the error.