David Cameron said yesterday that an independent inquiry should investigate evidence, revealed by The Independent, that British intelligence agencies were complicit in the rendition of terrorist suspects to Libya, where they were tortured by the Gaddafi regime.
Responding to the discovery on Friday of papers implicating MI6 in the arrest and extradition of Libyan dissidents, the Prime Minister said: "We've asked the retired judge Sir Peter Gibson to examine issues around the detention and treatment of suspects overseas."
Mr Cameron told the Commons that the accusations were "significant" and promised that fears the UK and Libyan security services became "too close" would be fully examined.
But he repeatedly praised the work of MI5 and MI6 and urged MPs to remember the context in which the intelligence services were operating as they tried to bring the Libyan regime in from the cold and recruit it in the fight against international terrorism.
"It is important that nobody rushes to judgement. In 2003, two years after 9/11, you had the situation where there was a Libyan terrorist group that was allied to al-Qa'ida. At that time our security services were working to keep us safe," Mr Cameron said.
Documents discovered in Tripoli appear to suggest the UK traded information with Colonel Gaddafi's government in return for intelligence extracted from terror suspects under interrogation in Libyan prisons.
The papers, discovered in the offices of the former head of Libyan intelligence, Moussa Koussa, imply that Britain was involved in the rendition of Abdelhakim Belhaj, who was at the time a member of the Libyan Islamic Fighting Group.
Now a commander in the rebel forces which overthrew Colonel Gaddafi with British support, he says he was held in isolation, and regularly tortured, during his three years in prison.
In a statement to MPs on Libya, Mr Cameron said: "My concern throughout has been to deal with these accusations of malpractice so as to enable the security services to get on with the vital work they do. And because they cannot speak for themselves, let me put on record once again our enormous gratitude for all they do to keep our country safe."
Jack Straw, who was the Foreign Secretary at the time of the events mentioned in the letter, said the previous government strongly opposed the use of torture and denied turning a blind eye to it.
A parliamentary inquiry could also be launched into the claims.
Mr Belhaj is planning to sue. "Britain, America, they demand that other countries follow laws on human rights. Are their intelligence people above the law?"