MI5 accepts it gave evidence based on lies in neo-Nazi spy case

MI5 has admitted for the first time that it gave evidence in court based on lies, following a BBC revelation that the security service defended a violent informant using fabricated testimony. The admission marks a significant moment for the UK’s domestic intelligence agency, which has never previously conceded that false evidence was presented in a criminal trial.

The case

The controversy centres on an MI5 operation in which the security service used an informant with links to neo-Nazi groups to gather intelligence on far-right extremism in the UK. The informant, who was active in the violent edges of the far-right scene, provided information to MI5 while continuing to engage in criminal activity himself.

When the informant’s conduct came under scrutiny in court, MI5 gave evidence in his defence. According to the BBC’s investigation, that evidence was based on claims that were later shown to be false. The security service has now confirmed to the BBC that the evidence it gave was indeed based on lies.

This is understood to be the first time MI5 has publicly admitted giving false evidence in court. The admission follows a BBC investigation that brought the matter to light, prompting a review within the agency.

Why it matters

The use of informants is a cornerstone of intelligence work, particularly in tackling far-right extremism, where open-source intelligence and surveillance often have limits. But the practice carries inherent risks: informants have their own agendas, may exaggerate or fabricate information, and can themselves be involved in the very criminal activity they are meant to help police.

When MI5 gives evidence in court, it does so as a witness of record. The integrity of that evidence is central to the fair trial rights of the accused. If an intelligence agency knowingly presents false testimony, that undermines the judicial process and exposes the convictions that flow from it to challenge.

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The admission is also politically sensitive. MI5’s credibility with the courts, with Parliament, and with the public rests in part on the accuracy and reliability of its evidence. An admission that testimony was given based on lies will fuel questions about what else the agency may have got wrong, and whether oversight mechanisms caught the problem in time.

What happens next

The organisers of the case, the defendants affected, and the relevant oversight bodies will now have to determine what the admission means for any proceedings that relied on the false evidence. In the UK system, where a criminal conviction has been obtained partly through evidence later shown to be unreliable, the defendant can apply to have the conviction set aside or the case reopened.

MI5 is expected to face questions from the Intelligence and Security Committee of Parliament and from the Investigatory Powers Commissioner’s Office about how the false evidence came to be given and why it was not caught sooner. The BBC’s reporting has already prompted the agency to acknowledge the problem; further scrutiny from lawmakers and the courts is likely to follow.

The case also raises broader questions about the governance of informant handling in UK intelligence. Standards for vetting, managing, and supervising informants vary between agencies, and the operation that gave rise to this controversy may prompt a review of those standards within MI5.