Public-interest immunity

Public-interest immunity (PII) is a principle of English common law under which the English courts can grant a court order allowing one litigant to refrain from disclosing evidence to the other litigants where disclosure would be damaging to the public interest. This is an exception to the usual rule that all parties in litigation must disclose any evidence that is relevant to the proceedings. In making a PII order, the court has to balance the public interest in the administration of justice (which demands that relevant material is available to the parties to litigation) and the public interest in maintaining the confidentiality of certain documents whose disclosure would be damaging. PII's have been used in criminal law against large organised criminal outfits and drug dealers where the identity of paid police informants could be at risk.