A doctrine that authorizes the nondisclosure of information or documents relevant to litigation on the basis that disclosure of such evidence is against the public interest. According to the doctrine of Crown privilege, only the Crown could apply to the court to suppress evidence on this basis, it being accepted that a ministerial affidavit or certificate to the effect that the production of certain evidence would be contrary to the public interest was conclusive. Crown privilege has now been replaced by public interest immunity, which enables any party or witness in any proceedings to apply for nondisclosure (R v Lewes Justices, ex p Home Secretary  AC 388). Where a claim of public interest immunity is made, it is for the court to weigh the interests of justice against the reasons for the claim of immunity. In the majority of cases this requires the court to inspect the documents. If, in the view of the court, the public interest would not be prejudiced by disclosure, production of the documents will be ordered (Conway v Rimmer  AC 910 (HL); Burmah Oil v Bank of England  AC 1090 (HL); Air Canada v Secretary of State for Trade (No 2)  2 AC 394 (HL); R v Chief Constable of West Midlands Police, ex p Wiley  AC 274 (HL).