Public Interest Immunity

Public interest immunity is a common law principle allowing a litigant to refuse to disclose evidence to other litigants on the basis that it would be damaging to the public interest.

During an investigation, the police may collect sensitive material which could undermine the case for the prosecution, and/or assist the case for defence. Nonetheless, it may be withheld by the Crown under the public interest immunity (PII) principle.

This means there may be a conflict between the general rule that the administration of justice requires that the defendant should have full access to all non-privileged, relevant material, and the PII doctrine that allows certain material to be withheld if it is not in the public interest to disclose it. In the latter case, the public interest is the overriding factor.

The relevant statutory provisions and codes are:

• Criminal Procedure and Investigations Act 1996 (CPIA 1996)
• The Criminal Procedure Rules 2005, Part 25
• Disclosure: Court of Appeal protocol for the control and management of unused material in the Crown Court, and
• Attorney-General’s Guidelines: Disclosure of Information in Criminal Proceedings

An application for PII will be made by the prosecution to the court. If the court orders that the prosecution do not have to disclose material to the defence, the defence may challenge that decision and the court may then either uphold its original ruling or order disclosure pursuant to the defence application.

Under the CPIA 1996, sensitive “material must not be disclosed…to the extent that the court, on an application by the prosecutor, concludes it is not in the public interest to disclose it and orders accordingly”. The main types of sensitive material are:

• National security/affairs and interests of state
• Journalists’ sources
• The prevention, detection and investigation of crime
• Material relating to children or young children

However, this list is not exhaustive, and each case turns on its own facts.

A claim may be justified on the grounds that disclosure would be prejudicial to national security. The test is whether disclosure would cause real harm to the public interest. Where a government minister is advised that disclosure of the material would cause real harm or threat to national security, a PII certificate to that effect must be signed. Once the risk to national security has been certified by an appropriate ministerial certificate, the court should not exercise its right to inspect as the certificate will be conclusive.

Section 10 of the Contempt of Court Act 1981 provides that a court may not require a person to disclose any source of information contained in a publication, unless the court is satisfied that it is in the interests of justice or national security, or for the prevention of disorder or crime to order disclosure. In the absence of one of these criteria, a person cannot be held in contempt of court for refusing to disclose.

The most common situations in criminal cases include:

Police informers: there is a clear public interest in protecting the identity of police informers, and a ruling may be made banning the disclosure of material that may identify an informer

Police observation posts: for the same reasons, the identity of those who allow their premises to be used for surveillance may be protected by a ruling based on PII

Police reports, manuals and methods: Reports between police forces and the DPP/CPS are protected by PII, as are manuals and descriptions of police methods dealing with, eg. crowd control, demonstrations and riots to ensure police methods/tactics are not frustrated

Information relating to children: certain documents and records maintained by social services and other agencies are protected by PII to safeguard the welfare of children

A ‘disclosure officer’ must provide a schedule of any sensitive material which he believes is not in the public interest to disclose, and why. Once material is determined to be sensitive it is listed on a separate form (‘MG6D’) which is used to assist the prosecution, but not disclosed to the defence.

The prosecutor will review the schedules and make decisions as to what material would ordinarily be disclosed, under the prosecutor’s initial or continuing statutory duty to disclose. The prosecutor must decide whether material, which otherwise would be disclosed pursuant to these tests, should not be disclosed on the grounds of PII.

The prosecution must manage PII applications in accordance with existing guidelines. If the defence is aware of a PII application, the defence can attend a hearing in open court, with the prosecutor present. Both the prosecution and defence are entitled to make representations to the court. However, the court will still consider the PII material ex parte with just the prosecution present.

The defence is entitled to apply for a review of a non-disclosure order by the court. If the defence is unsuccessful at its first attempt, it can apply at any time prior to conviction or acquittal for a review.

Once it is determined that certain material attracts PII, it is for the court to consider whether the interests of the defence can be protected while giving adequate protection to the public interest in question, which may be achieved by ordering limited disclosure.

The balance is between the public interest to withhold the evidence, and the interests of justice to disclose. If the disputed material MAY prove the defendant’s innocence or prevent a miscarriage of justice, then the balance comes down in favour of disclosure of the defence. Therefore, if there is a chance that the information may lead to an acquittal, the judge should order disclosure.

The prosecution must then decide whether to disclose the material, or abandon the prosecution in order to continue to protect, eg. the identity of an informant.