Public-interest immunity


Public-interest immunity, previously known as Crown privilege, 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 and the public interest in maintaining the confidentiality of certain documents whose disclosure would be damaging. PII orders 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.

Seeking the order

An order that PII applies would usually be sought by the British government to protect official secrets, and so can be perceived as a gagging order. Where a minister believes that PII applies, he signs a PII certificate, which then allows the court to make the final decision on whether the balance of public interest was in favour of disclosure or not. Generally, a court will allow a claim of PII without inspecting the documents: only where there is some doubt will the court inspect the documents to decide whether PII applies.
Originally, a government minister was under a duty to advance a PII point where PII could be relevant, and the court took a certificate from a minister claiming PII as final and conclusive. However, over time, there has been an increase in both the ability of a minister to make a disclosure, notwithstanding the potential application of PII, and the ability of the courts to review a claim of PII. In Conway v Rimmer , the House of Lords held that the courts retained the final decision on whether PII should be upheld, and, in R v Chief Constable of West Midlands, ex parte Wiley , the House of Lords decided that a minister could discharge his duty by making his own judgment of where the public interest lies. In practice, this is thought to have led to a reduction in the number of cases when PII is asserted.

History

PII was previously known as Crown Privilege, and derived from the same principle as the sovereign immunity of the Crown from prosecution before the Crown Proceedings Act 1947. However, PII is not limited to the Crown, and cannot be waived save in exceptional circumstances.
A number of PII certificates were signed in relation to the prosecutions of individuals involved in the Matrix Churchill "Arms to Iraq" case, a subject that was subsequently investigated in the Scott Report.

Examples

Article 6 of the European Convention on Human Rights protects the right to a fair trial; an "implied" right stemming from this is that of "equality of arms" – the idea that hearings should be adversarial and both parties should have access to the same evidence and witnesses. The European Court of Human Rights has held that Article 6 is not an absolute right and that measures restricting the rights of the defence so as to safeguard an important public interest are lawful if "strictly necessary".
It is of note that fewer PII certificates have been issued in recent years. For example, MI6 have not succeeded in obtaining a PII certificate since the 1995 Tomlinson case, and have thus been subject to court scrutiny for investigations such as the inquest into the death of the Princess of Wales, and allegations that their officers partook in torture.