Al Rawi and others v The Security Service and others  UKSC 34
The Supreme Court was asked to decide whether a ‘closed material procedure’ could be ordered in the trial of a civil claim for damages. Such a procedure would permit the Security Service to rely on evidence alleged to be security sensitive, without such evidence being disclosed to the claimants. Instead the claimants’ interests would be represented by Special Advocates, who could not take instructions from them, as was familiar from the statutory scheme for hearings by the Special Immigration Appeals Commission. The question arose in the context of claims brought by a number of those suffering detention, rendition and mistreatment by foreign authorities with the alleged complicity of the British security services. By a majority, the court held that there was no power at common law to introduce such a procedure: only Parliament could make such a change. It involved a departure from the principles of open and natural justice, which were essential features of a fair trial. It could not properly be regarded as a development of public interest immunity, by which a court can rule that certain material can be excluded from the hearing altogether where the public interest requires this.