In January 2022 a senior MI5 officer told a High Court judge, in a signed statement, that the service had never confirmed to a journalist who one of its informants was. The government was trying to stop the BBC from naming that man. In the summer of 2020 an MI5 officer, with permission, had confirmed exactly that to the BBC journalist over nine phone calls — and the journalist had notes, and recordings of some of them.
The false statement misled the High Court in two separate cases and a special tribunal, and it stood for almost three years. In September 2026 MI5 accepted without reservation an official report finding that the evidence it gave was based on lies. None of the people whose job was to check found it.
The natural answer is that the checks were not really independent. That turns out not to be true. The judges owed nothing to MI5. The Investigatory Powers Tribunal, a special court that hears complaints against the spy agencies, is made up of senior lawyers and judges. The Investigatory Powers Commissioner exists to watch those agencies, and was misled too.
And the judge who heard the BBC case, Mr Justice Chamberlain, had spent years as a special advocate inside exactly these secret hearings. In 2012, as a barrister, he wrote that they belonged in a novel by Kafka. He was misled anyway.
Normally each side sees the other side's evidence and can attack it. That is how a court finds lies. Since the Justice and Security Act 2013, British courts can hear part of a civil case in a closed procedure: the secret part is heard only by the judge and a special advocate, a security-cleared lawyer who argues for the side that is shut out.
Once the special advocate has seen the secret material, they may not discuss it with the people they defend. They can only ask the state. The side that might know whether the secret evidence is true is the side that cannot hear it.
The judge had MI5's statement. In the secret part of the case the special advocates acting for the BBC asked MI5 direct, precise questions and twice received false answers; the BBC itself never heard them. The tribunal and the commissioner relied on the same statement. Every one of them was independent of MI5, and every one of them learned the facts from MI5.
The court put it in one sentence: the proper operation of each of these safeguards depends on high standards of candour from the agencies. The falsehood came to light only when the journalist later found his notes and recordings. MI5's two commissioned inquiries never contacted him; the court found their conclusions could not be relied on.
Refuse secret evidence. In Al Rawi (2011) the Supreme Court held that judges have no general power to hold secret hearings in ordinary civil cases. Price: while the courts were still deciding, the government settled with former Guantanamo detainees rather than disclose its evidence — confidential sums, no admission of fault, and no court ever found out what happened. That was the government's own argument for the 2013 law.
Put a real opponent in the room. An opponent who reads only the agency's paper has what the special advocates had; it becomes a second source only if it can talk to the people outside, and every extra person who hears a secret is another way for it to leak. So access is rationed: the US surveillance court's outside lawyers (2015) are called in only when judges choose. Four judges approved the Carter Page applications without one; the inspector general later found seventeen significant errors and omissions.
Make every claim traceable and every lie expensive. Documents behind each asserted fact, named sources, sanctions. The FBI has had such rules since 2001; British judges ordered something similar after this case. Price: paper checks rest on the agency's own paper — in a sample of 29 other FBI applications, four had no supporting file at all, and 209 errors were counted.
Nobody required the journalist to record those nine calls, and no law could have. They were the only record of those calls that had not passed through MI5's hands, and nothing in the system had asked for them.
When you are told something has been independently checked, ask not who did the checking, but where the checker got the facts — and whether any of them came from somewhere else.