Prime Minister orders investigation into MI5 over false evidence in Agent X case

The prime minister has ordered a fresh investigation into how MI5 supplied false evidence to two courts and to the office that oversees its surveillance activities, after senior judges rejected the security service’s explanations in a high-profile informant case.

Sir Keir Starmer on Tuesday directed the Investigatory Powers Commissioner, Sir Brian Leveson, to commence an immediate inquiry into the circumstances that led to inaccurate material being presented to the High Court and the Investigatory Powers Tribunal in relation to an informant known as "Agent X." The prime minister said the courts "will use the outcome of this investigation to determine their next steps in relation to the case of Agent X."

The case centres on a man who was handled by MI5 as an undercover source and who has been described in reporting as a neo‑Nazi. The BBC revealed in February that MI5 had given false evidence to three courts while defending its handling of the agent, whose activities included coercing his former partner and an attack in which she was assaulted with a machete. In its defence, the Security Service had told judges it had followed its policy of neither confirming nor denying the identities of informants. The BBC reported it had obtained recordings and other evidence showing MI5 officers disclosed the agent’s status in phone calls to journalists and tried to dissuade them from investigating him.

MI5’s director general, Sir Ken McCallum, issued a public apology after the BBC’s revelations. Two internal or agency-led inquiries subsequently cleared MI5 and individual officers of deliberate wrongdoing, attributing the false evidence to mistakes and faulty recollections. However, a panel of senior High Court judges in July found those investigations "suffered from serious procedural deficiencies" and concluded the courts could not rely on the prior findings. The judges said it would be premature to start contempt of court proceedings against MI5 officers until a further independent investigation took place.

The Investigatory Powers Tribunal reached a similar conclusion later that month, rejecting MI5’s explanations and requesting a new inquiry. The Investigatory Powers Commissioner’s Office (IPCO), which provides oversight of the Security Service’s use of investigatory powers, was itself given inaccurate information by MI5 in the matter and will now lead the fresh probe under Sir Brian Leveson’s authority.

In his written statement to Parliament, Sir Keir said the relevant courts had found MI5’s investigations "suffered from serious procedural deficiencies" and that a new investigation was necessary. He added that he had "issued a direction to the Commissioner to commence this investigation immediately."

A Home Office spokesperson said the home secretary was "concerned that inaccurate evidence was provided to the High Court and Investigatory Powers Tribunal," and noted that the director general of MI5 had "rightly apologised for this serious failing, both publicly and to the Courts." The spokesperson said the government accepted the courts’ recommendations and that it would be inappropriate to comment further until the commissioner's probe is completed.

Legal observers said the outcome of Sir Brian Leveson’s investigation will inform whether further legal steps, including possible contempt proceedings, are appropriate. The High Court in July explicitly left open the possibility of contempt action pending the results of a fresh, independent review. The Investigatory Powers Tribunal likewise indicated its decision-making would be informed by the commissioner’s findings.

The incident has raised questions about MI5’s internal record-keeping, supervisory arrangements for informants and the handling of sensitive material in legal proceedings. MI5 has acknowledged the errors identified to date and apologised; the new inquiry will examine how incorrect evidence came to be presented to judicial bodies and oversight officials, and whether further accountability measures are warranted.

Sir Brian Leveson, who leads IPCO, is a former senior judge who holds statutory responsibility for oversight of the use of investigatory powers by the security and intelligence agencies. The commissioner’s office will now begin its inquiry at the direction of the prime minister, and courts have indicated they will await its conclusions before deciding on subsequent legal or disciplinary action.