There are instances when a litigant, whether it is a plaintiff or defendant, during the course of a court trial, is allowed by the court not to reveal evidence because such evidence would prove to be detrimental to public interest. Such cases refer to public interest immunity, a British common law principle that allows evidence to remain undisclosed if there is a possibility that it may do harm in terms of public safety.
Historically, public interest immunity was derived from crown privilege, which prevented royal individuals, especially the reigning king or queen, from being prosecuted. However, the Crown Proceedings Act of 1947 reneged this privilege but the idea of preventing certain people or information from undergoing litigation was based on this privilege.
It is the rule that all litigants must disclose evidence within the duration of the court trial. An exception to this rule is public interest immunity. It is important that the court, before deciding to provide public interest immunity, must balance the delivery of justice upon the revelation of all pertinent information and the protection of the public’s well-being. Thus, public interest immunity must answer both elements before it can be given to a litigant.
Public interest immunity may apply to cases that involve releasing sensitive information such as that which may compromise national security or state secrets. It is also imperative to withhold the identities of witnesses or informants who can provide crucial testimonies in a court case. This usually ensures the safety and integrity of the people and the information, which have been undisclosed.