Spiral staircase

Evidence and Disclosure

Introduction to Evidence and Disclosure

Gavel and books

MI5 officers have been witnesses in
high profile criminal trials

Beginning in the 1990s, changing threats to national security and developments in the law have seen us become more engaged in the criminal justice process.

MI5 officers have been witnesses for the prosecution in a number of high profile criminal trials, and MI5 material has either been admitted in evidence or disclosed to the defence in various cases. This has occurred mostly in the context of our counter-terrorism work.

Our greater involvement in criminal proceedings means that we keep in mind the needs of both the law of evidence and the Crown’s duty of disclosure when we plan and carry out intelligence investigations which may lead to a criminal prosecution.

Our officers work closely with members of law enforcement agencies. They ensure that operations are properly co-ordinated so that resulting intelligence product can potentially be used as evidence in court. For these reasons, as well as to ensure proper internal controls and compliance with our legal obligations under the Regulation of Investigatory Powers Act 2000 (RIPA) and other relevant legislation, we keep detailed records of our operations. This includes meetings with agents (CHIS), and eavesdropping, search and surveillance operations.

Judges have allowed our staff to give evidence in criminal trials anonymously, including appearing behind screens. These arrangements are similar to those that are made for undercover and specialist police officers and members of the Special Forces when giving evidence. The decision on these issues, however, rests with the trial judge in each case. The evidence given by MI5 witnesses remains subject to cross-examination by the defence in the normal way, even where the judge makes an order for the witnesses’ screening and anonymity.

As for  intelligence that is not relied on by the prosecution in evidence but which is potentially relevant to the case, the duty of prosecutors to review such material  and to disclose it to the defence if it is reasonably capable of undermining the prosecution case or assisting the defence case applies equally to MI5 material .

Protecting sensitive information

The courts do however recognise that the duty of disclosure must be balanced against the need to protect sensitive information. Where an investigation leads to a prosecution, prosecuting Counsel considers our records and advises which information meets the disclosure threshold and falls to be disclosed to the defence. If the information in question is sensitive, such as the identity of an agent (CHIS) or details of a sensitive investigative technique, its disclosure could cause real damage to the public interest in the protection of national security. In such cases, the prosecutor may apply to the judge for authority to withhold the material. Such applications take the form of a claim for public interest immunity (PII).

Claims for PII in relation to our material are made on the basis of a certificate signed by the Secretary of State, usually the Home Secretary. In deciding whether a claim is appropriate, the Home Secretary has to carry out a careful balancing exercise. The competing public interests in the administration of justice and the protection of national security must be weighed. This exercise takes account of detailed advice from prosecuting Counsel on the relevance of the material to the issues in the case.

If the Home Secretary considers that the balance favours non-disclosure, a claim for PII will be made. But the decision on a PII claim is ultimately one for the trial judge alone. The courts, not MI5 or the government, ultimately decide what must be disclosed in a particular case. If a claim is accepted, the judge will nevertheless continue to keep the decision to authorise non-disclosure of the sensitive material under review throughout the proceedings.

Proceedings arising out of MI5-recommended disruptive measures

MI5 frequently uses intelligence as evidence in the Special Immigration Appeals Commission (SIAC) and the High Court in cases arising from immigration decisions, TPIMs (Terrorism Prevention and Investigation Measures) or other action taken by ministers to protect national security.  SIAC is a superior court of record with the purpose of hearing appeals and judicial reviews against immigration and nationality decisions taken on national security grounds.

SIAC has special procedures which are designed to enable it to take account of sensitive evidence, including sensitive intelligence material. Where evidence is not sensitive, SIAC sits in "open" session. The appellant and his or her lawyers may participate in open sessions in the normal way. Members of the public may also attend the proceedings.

However, SIAC also uses "closed" sessions to hear evidence that the court agrees must be withheld from the appellant in order to avoid damage to the public interest in, for example, the protection of national security. The appellant and his or her lawyers, and the public, are excluded from closed sessions. A "special advocate" drawn from a panel of security-cleared Counsel represents the appellant’s interests instead. The special advocate may make submissions and cross-examine witnesses in the same way as the appellant's own lawyer in open session.

The closed material procedure in the High Court in TPIM and asset freezing proceedings is essentially the same as that in SIAC.

MI5 officers have given evidence in many SIAC and TPIM cases to date. They have done so both in open session (when they are screened in order to protect their identities) and closed.

Civil Proceedings

A PII claim may also be made to protect sensitive information relevant to civil litigation. Additionally, the Justice and Security Act 2013 provides that a court may order a "closed material procedure" in certain civil proceedings in order to ensure that sensitive material can be considered as part of the case, while also being adequately protected. This now enables MI5 to rely on sensitive material in our defence when we face actions for civil damages, providing the judge is satisfied that a closed material procedure is necessary to ensure the fair and effective administration of justice. As in SIAC, special advocates may be appointed to represent the interests of claimants in closed material procedures.

MI5 may also hold material of relevance to a range of public inquiries. In such cases we will disclose the material with necessary redactions or, where the material is too sensitive to be disclosed, we will apply for a “restriction notice” under the Inquiries Act so that the material is only considered by the Inquiry Chair and team within a closed session. 

Where MI5 holds material relevant to the circumstances of a death, the material may need to be considered in inquest proceedings. In such cases MI5 will work closely with Counsel to the inquest to ensure all such material is identified and shown to the coroner or judge with conduct of those proceedings to ensure the proceedings are conducted fairly. PII may also be used to protect material from subsequent disclosure to the interested persons.


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