MI5 gave false evidence to the courts while defending its handling of a neo-Nazi informant accused of abusing his girlfriend. The watchdog that oversees the service has now found serious and systemic failures in how it behaved.
It found MI5 knew what he was.
The informant can be named only as Agent X because of a court order. He is a foreign national, and his former girlfriend, known as Beth, alleges that he subjected her to coercive control and used his links to MI5 to keep her silent.
The Investigatory Powers Commissioner’s Office, which oversees MI5, found the service knew Agent X was obsessed with violence and openly misogynistic. It was aware he had threatened Beth with a machete. None of this led to a review of his suitability as an agent, and it described a lack of sufficient professional curiosity among his handlers about the danger he might pose.
MI5 had long relied on its policy of neither confirming nor denying who works for it. A report published on 16 July 2026 by the Investigatory Powers Commissioner, Sir Brian Leveson, and led by his deputy Sir John Goldring, found that an officer departed from that policy in dealing with a BBC journalist, discussing Agent X’s role. He knew what he had done and failed to report it. Others in MI5 knew too, yet a false account was allowed to take hold and persist.
That false account was then relied on in injunction proceedings, before the Investigatory Powers Tribunal and in judicial review. MI5 gave false or misleading evidence to the High Court and to the tribunal, and it wrongly assured the watchdog itself that the policy had been maintained. The tribunal said the false evidence gave rise to real cause for concern and must never happen again.
The position held until a recording confirmed that the officer had discussed Agent X’s role with the journalist. MI5 was then forced, exceptionally, to confirm that he had been an agent.
Sir Ken McCallum, the director general of MI5, has apologised to both courts for the incorrect evidence and for the service’s slowness in recognising what had happened. He said MI5 recognised without hesitation the seriousness of its failings, and apologised again to Beth.
An apology is not the same as accountability.
MI5 settled Beth’s claim around March 2026 and paid her compensation. The courts had put off deciding whether to bring contempt proceedings over the false evidence until this investigation reported. With the report now published, that question returns to them.
Shabana Mahmood, the Home Secretary, said she was taking urgent action to hold MI5 to account, including strengthening her oversight and assurance of its work.
Strengthened oversight is welcome, but it is a promise about the future. It does not settle the question of individual accountability in this case, which the courts have still to resolve.
In this case, MI5 clung to secrecy long after one of its own officers had let the truth slip. A woman seeking justice was left in the dark, and the question of who answers for that now sits with the courts.