A former civil servant has accused the government of an attempt to cover up “crimes” by the former British ambassador to the US, who he claims leaked intelligence to his lover. Andrew Hale-Byrne is suing the foreign secretary, James Cleverly, and the international trade secretary, Kemi Badenoch, alleging that he was arrested in order to divert attention from Sir Kim Darroch, the former UK ambassador to the US. Hale-Byrne was arrested by counter-terrorism police at his home in 2020 while recovering from cancer surgery over allegations he leaked diplomatic cables in which Darroch criticised Donald Trump. Hale-Byrne denies being the leaker and was never charged. In his legal claim, he alleges that his arrest was designed to deflect attention from Darroch, who he claims was leaking intelligence – unrelated to the cables – from the Five Eyes alliance. Hale-Byrne alleges Darroch was having an affair with a CNN correspondent and provided her with classified information. The correspondent has denied having an affair with Darroch or that she received intelligence from him. A story about the alleged affair in the Sun was later taken down. At an online high court hearing on Tuesday, the judge, Master Davison, heard arguments as to whether the government can submit a “closed” defence. Closed material can only be viewed by special advocates who cannot discuss the evidence with anyone else, including the parties – and their regular lawyers – in the case. In a statement by Hale-Byrne, read to the court by his barrister, Paul Diamond, the claimant said there was an “official UK government cover-up of Kim Darroch’s crimes” and it was using the Justice and Security Act, which is normally employed in terrorism cases, to do so. He said: “The civil service is attempting to weaponise counter-terrorism legislation in an effort to block the press and the public from my high court claim against James Cleverly and Kemi Badenoch. Any corrupt or foolish Tory government minister who signs off on an application under the Justice and Security Act to block the press and the public should be ashamed of themselves for such Soviet-style behaviour. We expect this behaviour from totalitarian regimes, such as Russia, China, and North Korea, but it is an outrage this could now happen in the UK.” With a number of press present, Davison said Hale-Byrne’s statement appeared to be aimed at the “public gallery”, while Adam Heppinstall KC suggested that the real reason for the hearing, which he branded “unnecessary”, was “so the claimant’s statement could be read”. Diamond told the court the government was attempting to “misuse” the Justice and Security Act but Davison granted permission for a closed defence to be filed, which a judge will then review to assess the need for secrecy. The claimant was ordered to bear the costs of Wednesday’s hearing. Darroch resigned as the US ambassador in July 2019, after the then foreign secretary, Boris Johnson, refused to back him after the leak of cables in which Darroch described the Trump administration as dysfunctional, clumsy and inept and the former president as radiating insecurity. Diamond told the court that the US Congress was considering holding hearings into the allegations against Darroch. Hale-Byrne was allegedly arrested the day after the Sun approached Darroch for a right to reply for the story relating to the alleged affair. The civil servant was said to have been profoundly affected by the experience, becoming homeless and suicidal.