MI5 colluded in the questioning under torture of the convicted British terrorist Rangzieb Ahmed in Pakistan in 2006-07, the high court heard on Tuesday as part of a civil claim brought by him against the spy agency and the government. The security services are accused by Ahmed of suggesting to Pakistan’s Inter-Services Intelligence (ISI) agency that they arrest him in 2006, and of submitting questions, which were put to him under torture, during which three of his fingernails were ripped out. Richard Hermer QC, representing Ahmed, told the court that “this case contains serious allegations about the conduct of the security services” and said it was one of a handful of cases in which the spy agencies were accused of being complicit in torture at the height of the “war on terror”. The collusion allegations emerged on the first day of a court hearing in which government lawyers are seeking to have Ahmed’s long-running civil claim struck out, arguing that he is effectively trying to reopen his terror conviction. The Guardian and a group of other media organisations also had to appeal to the judge, Mr Justice Garnham, at the outset of the two-day hearing to ensure the proceedings were held in public. Garnham said he would hold as much of the case in open court as possible. Ahmed was found guilty in 2008 of directing terrorist activities for al-Qaida and sentenced to life imprisonment, a conviction that was subsequently upheld by the court of appeal three years later. Rory Phillips QC, representing the spy agencies and the government, accused Ahmed of pursuing “a collateral claim” – trying to relitigate a matter that had already been determined by the criminal courts – and said it should be immediately halted. Ahmed was under surveillance when he was in Britain and Dubai in 2005, but his legal team says he was allowed to travel to Pakistan in early 2006 where he was arrested a few months later in August at the “suggestion” of the British government. During 13 months of detention by the ISI before he was deported to the UK, Ahmed said he was a victim of torture where he was handcuffed in a cell without daylight, deprived of sleep, beaten with a stick and had three fingernails pulled out by pliers. Ahmed’s legal team also claimed he was asked questions under torture about the UK by ISI officers, that he saw “UK/Pakistan secret” at the top of a question list used by the Pakistani agency, and that early on in his detention he was visited by officers from both MI5 and MI6, where he complained about mistreatment. However, Phillips told the court that the criminal courts had already examined Ahmed’s allegations, and cited the court of appeal ruling which noted, with approval, that the lower court had “expressly rejected the suggestion of outsourcing torture by British authorities”. Ahmed’s lawyers say the civil and criminal claims are different, and argue that evidence of similar mistreatment and collusion has emerged in other cases, such as Binyam Mohamed, a British resident who says MI5 knew he was mistreated and tortured when he was detained in Pakistan in 2002. David Cameron when he was prime minister promised a judge-led inquiry into allegations of torture and rendition involving Britain’s spy agencies during the “war on terror”. But his successor, Theresa May, abandoned the promise on her last day in office. Two MPs, David Davis and Dan Jarvis, are leading a challenge to that decision. Garnham is expected to reserve judgment once the hearing concludes.