MI5 gave evidence based on “lies” to three courts while defending a violent neo-Nazi spy whose abuse was uncovered by the BBC, a damning official report has found.

The report, by the deputy investigatory powers commissioner Sir John Goldring, heavily criticises a series of senior MI5 figures and their organisation.

He finds that one senior MI5 officer lied repeatedly, while another misled his own colleagues and lied about what he was told.

The conclusions confirm the BBC’s revelation in February last year that MI5 lied to the courts, something the security service vehemently denied.

Sir John’s investigation was ordered by the prime minister in September after MI5’s explanations about what happened were rejected as deficient and unreliable by the High Court.

His new report will plunge MI5 into crisis and could result in contempt of court proceedings or even a criminal prosecution.

“MI5 recognises without hesitation the seriousness of our failings in these proceedings,” said MI5 Director General Sir Ken McCallum.

“I repeat my previous apologies to both courts for the incorrect evidence that was provided, and for our slowness in recognising what had happened.”

Home Secretary Shabana Mahmood said the findings of the report were stark.

“It details serious failings by individual MI5 officers, resulting in false evidence being provided to the courts, and criticism of MI5 as an organisation,” she said.

“I am taking urgent action to hold MI5 to account for these failures, including strengthening my oversight and assurance of their work.”

The investigation examined how MI5 gave false evidence to three courts about having kept to its core secrecy policy – known as ‘neither confirm nor deny’ (NCND) – about the agent status of the violent neo-Nazi informant.

MI5 claimed it had maintained NCND and, consequently, the courts allowed it to keep information secret from a woman who was abused by the informant.

But what MI5 said was untrue.

MI5 had in fact disclosed the man’s agent status in phone calls to me, as it tried to persuade me not to investigate him in 2020.

A senior MI5 officer, known as Officer 2, had tried to cover up for the man, falsely saying he was not an abusive misogynist nor a real extremist.

He even wanted me to meet the agent. In doing so, he repeatedly departed from the NCND policy.

The new report finds:

  • The senior MI5 officer, Officer 2, repeatedly told “lies” and these “formed the foundation of MI5’s false account” to the three courts. He “put forward a wholly fictitious account” in which he denied ever telling me that X was an MI5 agent.

  • A separate senior MI5 officer, Officer 3, “misled” his own colleagues and did not act in good faith. The report concludes that he “bears considerable responsibility for the continuation of MI5’s falsehood” because he “misrepresented” what Officer 2 had said to him. He was not “truthful” about warnings he received from colleagues.

  • An MI5 deputy director, Witness A, who gave his organisation’s witness statements to the courts “overstated” matters during a key internal meeting and a note of his comments was “misleading”. He therefore “contributed to MI5’s continued reliance on the false account”.

  • Various people in MI5 knew NCND had been departed from and there was “cogent evidence” in case files showing it had been, but the falsehood was nevertheless “allowed to take hold and persist”. Afterwards, “opportunities to correct the position were missed” by MI5.

  • Even MI6 and a foreign intelligence agency were told that NCND had been departed from. Despite this, MI5 repeatedly told the courts it had not been, and supposedly ‘independent’ reviews of what happened said no one beyond Officer 2 knew what had happened and that he had forgotten.

  • There were “serious and systemic failures in MI5’s conduct” throughout the case.

The case centres on an MI5 informant known as Agent X, a foreign neo-Nazi misogynist who used his security service role as a tool of abuse.

He coercively controlled his British partner, known by the alias Beth, and attacked her with a machete. MI5 then helped him go abroad to continue intelligence work while under police investigation.

The government took the BBC to court in 2022 in a failed attempt to block our investigation into X but won him legal anonymity. Beth then sued MI5 at the Investigatory Powers Tribunal (IPT), and in 2024 she sought a review of a ruling at the high court.

Arguing for secrecy in all three courts, the security service told judges it had always stuck to its NCND policy and never told anyone whether X was an agent, including me – as the BBC journalist who had investigated him. The courts were told this in a sworn statement from a senior officer, a deputy director called Witness A.

The courts accepted MI5’s arguments. This meant Beth and everyone else was banned from ever officially being told X was an agent and denied access to the key evidence. She was left at a serious disadvantage and may have lost the case.

Following this decision, in late 2024, I challenged MI5 and said they had lied to the courts. MI5 aggressively maintained its position that NCND had been maintained until I produced evidence proving it was untrue, including a recording of one of the calls with Officer 2.