Public Interest Immunity ("PII") is an immunity from the production of documents or information where their disclosure would be against the public interest. PII is a common law doctrine, developed to allow the courts to reconcile any potential conflict between the following two public interests—

(a) the interest in the administration of justice which demands that relevant material is available to the parties to litigation; and
(b) the interest in maintaining the confidentiality of certain documents whose disclosure would be damaging to the public interest.