Barry Manners & Ors v The Cabinet Office & Ors

Public interest immunity requires a staged inquiry. The decision-maker must ask whether the material would otherwise be disclosed, whether disclosure would create a real risk of serious harm to the public interest, and whether that risk can be mitigated by confidential disclosure or a gist. If a real risk remains, the court must balance non-disclosure against the public interest in a fair trial and the due administration of justice. A minister or permanent under-secretary supplies a certificate after performing that assessment, but the court is the ultimate decision-maker. The application was granted because gists substantially mitigated some material and no lesser measure safely protected the remaining material.

Passengers and crew of British Airways flight BA149 brought claims against the Government defendants and British Airways concerning their detention and mistreatment by Iraqi troops after the invasion of Kuwait. The claimants alleged that the Government defendants failed to respond adequately to warnings of invasion and intentionally used the aircraft to deploy military or quasi-military personnel.

The Government defendants applied, supported by public interest immunity certificates, to withhold relevant material identified during disclosure. The claimants and British Airways urged close scrutiny, particularly concerning whether UK Special Forces were on the aircraft. The central issue was whether non-disclosure was justified and whether partial disclosure or gisting could adequately protect the public interest.

Application granted. The Government defendants were permitted to withhold the material covered by the application on grounds of public interest immunity, subject to minor points being addressed in the final form of disclosure.

1. The court accepted that a public interest immunity claim requires assessment of whether the material would otherwise be disclosed, whether disclosure would create a real risk of serious harm to the public interest, and whether that risk could be mitigated by disclosure in confidence or by providing a gist. If a real risk exists, the competing public interests must be balanced.

2. The minister or permanent under-secretary must undertake that assessment and issue a certificate where the overall public interest does not favour disclosure. The certificate assists the court, but the court remains the ultimate decision-maker. The three questions were identified by reference to Chief Constable of West Midland Police ex parte Wiley [1995] 1 AC 274.

3. The court applied the principles stated in The Secretary of State for Northern Ireland [2026] 2 WLR 109. It considered whether partial disclosure could convey the gist of the information or otherwise mitigate the harm. The gists provided by the Ministry of Defence amounted to substantial mitigation. For material which could not be gisted, no measure short of non-disclosure would adequately safeguard the public interest.

4. After considering the documents and submissions in closed session, the court found a significant public interest in excluding the withheld information. In particular, the Government’s neither-confirming-nor-denying response concerning possible UK Special Forces involvement was justified. Its utility and importance depended on maintaining the response except in the most unusual circumstances.

5. The public interest balance therefore favoured non-disclosure.