MI5 and its director general, Sir Ken McCallum, will not face contempt of court proceedings, the High Court ruled, despite the intelligence service admitting to providing false evidence to three courts regarding a neo-Nazi informant. The agent, known only as X, allegedly exploited his role with MI5 to threaten and abuse his girlfriend, identified as Beth.

In July, Deputy Investigatory Powers Commissioner Sir John Goldring found "serious and systemic failings" within MI5 concerning the case. His report concluded that one senior officer repeatedly lied, while another misled colleagues and misrepresented information received about the case. Beth's lawyers had argued that MI5 and Sir Ken should face contempt proceedings, alleging "sustained and long-lasting" dishonesty and repeated efforts to prevent the truth from emerging.

MI5 initially confirmed Agent X's informant status to the BBC to dissuade a journalist from publishing the story, citing fears for X's safety. However, during subsequent court proceedings involving Beth and the BBC, the agency publicly maintained a policy of "neither confirm nor deny" regarding its relationship with X.

In an unprecedented move, MI5 has since paid compensation to Beth and issued a public apology to settle the case. The identity of Agent X, described as a foreign national involved in neo-Nazi movements, remains unknown, and he is understood to have left the UK.

Sir Ken McCallum acknowledged the service "fell badly short" in this instance. Lawyers for MI5 argued there was "no basis" to hold Sir Ken vicariously liable and no "strong case" for corporate liability in criminal contempt proceedings. They stated the agency is committed to making changes, but that contempt proceedings were "not now necessary or appropriate."