A Libyan Islamist who is now the military commander of the capital, Tripoli, is suing Britain for its role in his rendition into imprisonment and torture at the hands of Muammar Gaddafi's regime.
Abdelhakim Belhaj said he has taken recourse to legal action after waiting in vain for the British government to offer an apology for his seven years of incarceration in the secret police's jails.
The central plank of his case would be information from files discovered in Tripoli by The Independent after the fall of Colonel Gaddafi's regime. They contained letters from Sir Mark Allen, then MI6's head of counter-terrorism, to Moussa Koussa, the head of Libyan intelligence, in which he appears to boast about the key role played by his service in the capture and transportation of Mr Belhaj.
In a previous interview with The Independent, Mr Belhaj said he told British intelligence agents who had visited him in Tripoli of his mistreatment. "They knew I was being tortured," he said. "I hoped they would do something about it. I was too terrified during the meeting to say out loud what was being done to me because I thought the Libyans [secret police] were taping what was going on. When the guards left I made sign movements with my hands. The British people nodded, showed they understood. But nothing changed; the torture continued for a long time."
There was nothing to suggest in a tranche of MI6 papers that the UK raised concerns about his ordeal with the regime. Instead, there are repeated requests to the Libyan secret police for information about Mr Belhaj, including one believed to be from Sir Mark, who now works for BP, when arranging Tony Blair's visit to meet Colonel Gaddafi. "I was grateful to you for helping the officer we sent out last week. Abu Abd Allah's [a nom-de-guerre for Mr Belhaj] information on the situation in this country is of urgent importance to us."
Mr Belhaj, a former head of the Libyan Islamist Fighting Group, was arrested with British help along with his wife, Fatima Boucher, in 2004 and handed over to the Americans, who passed them on to the Libyan authorities. Ms Belhaj was released after four months.
Their cases are now the subject of a wider British inquiry into allegations of complicity by UK security agencies in prisoner abuse and officials in London hold that no apology can be legally given to Mr Belhaj and his wife while the investigation continues.
Mr Belhaj achieved one of the most important military posts in post-revolutionary Libya and was expected to be appointed Defence Minister. But the country's new Prime Minister, Abdurrahim al-Keib, chose a broadly secular cabinet with the post going to Osama al-Juwali.
Mr Belhaj's solicitors are acting on behalf of Iraqi civilians who had allegedly suffered maltreatment in the hands of British forces. Sapna Malik, from Leigh Day, said: "The barbaric treatment which our clients describe, both at the hands of the Americans and the Libyans, is beyond comprehension and yet it appears that the UK was responsible for setting off this chain of events."