Jack Straw faces legal action over allegations he personally approved rendition of Abdel Hakim Belhadj

Jack Straw, the former Foreign Secretary, faces a court cross-examination over allegations he personally approved the rendition of a Libyan military commander.

Lawyers representing Abdel Hakim Belhadj took the dramatic step of serving legal papers on the senior Labour MP following claims he gave the go-ahead to the illegal operation.

Mr Belhadj claims Britain was complicit in his seizure by the US and return to Libya, where he was jailed and tortured by the Gaddafi regime for six years.

Mr Straw has always appeared to deny approving or even knowing about the rendition – a denial recently echoed by Tony Blair.

However, fresh claims have surfaced that he authorised the operation.

The Independent has been told that he was approached recently by Foreign Office lawyers and shown evidence apparently contradicting his public statements.

Mr Belhadj’s lawyers, who are also representing another Libyan man, Sami Al Sadadi, have called for the former Foreign Secretary to produce all the paperwork relating to the case, as well as his diaries and notes over the relevant period.

The Metropolitan Police are already examining allegations of rendition. The Libyans’ lawyers, Leigh Day and Co, say the recent claims of Mr Straw’s alleged complicity in the rendition could lead to a criminal prosecution.

Mr Straw, the MP for Blackburn, has denied approving any unlawful rendition operations, or having any knowledge of them. Last autumn he said it had always been the position of Foreign Secretaries that they were opposed to unlawful rendition, were “not complicit in it” and did not “turn a blind eye to it”.

He said yesterday: “I am sorry that I can’t say more about this case, but with a police investigation pending and this intended civil legal action, I am sorry that it is not appropriate for me to say any more about it.”

The lawyers said Mr Belhadj was claiming damages personally from the former Foreign Secretary in recompense for the “trauma involved”. But they stressed his main aim was to seek an apology for the events and for the truth to emerge.

Sapna Malik, a partner at Leigh Day & Co, said: "We have said all along that liability must follow the chain of command.

“These latest revelations bring us closer to that goal. If the former foreign secretary does not now own up to his role in this extraordinary affair, he will need to face the prospect of trying to defend his position in court.”

Cori Crider, legal director of Reprieve, said: "At last it seems we know who signed off Britain's involvement in rendition to torture.

“Jack Straw must come clean with Mr Belhadj, Mr al Saadi and their families. They deserve an apology for the appalling way they were treated.”

Amnesty International's Europe and Central Asia director John Dalhuisen said: "This latest announcement of legal action by a rendition victim could be an important step towards accountability through the civil courts."

He added this was "an ongoing reminder of the failure by UK authorities to establish a human rights-compliant inquiry into these and wider allegations of UK involvement in torture and other human rights violations, in Libya and elsewhere.”

A Downing Street spokeswoman said: "The Government's position on torture is well-known. We stand firmly against it and any cruel, inhuman or degrading treatment or punishment. We do not condone that and we do not ask others to do it on our behalf.

"We take the allegations very seriously. What is important now is to ensure a fair trial and civil proceedings when people accuse the Government of mistreatment and seek compensation.”

Who is Abdel Hakim Belhadj?

Today, as the head of the Tripoli Military Council, he is a powerful figure with the Libyan transitional government.

Before last year’s civil war he was one of the most prominent rebels calling for Muammar Gaddafi’s removal from power. He led the Libyan Islamic Fighting Group, which was previously listed by Britain and the US as a terrorist organisation. It was also accused by the Gaddafi regime of links with al-Qa’ida – a claim it strongly denied.

How did he come to be arrested?

Following a tip-off from MI6, Mr Belhadj was arrested in March 2004 with his pregnant wife, Fatima Bouchar, as they attempted to fly from Malaysia to Britain. They were picked up when their plane stopped in Thailand, handed over to the CIA and returned to Libya. According to documents uncovered following Gaddafi’s fall, the “rendition” flight carrying the couple refuelled on the British island of Diego Garcia.

What happened to them in Libya?

Mr Belhadj spent six years in jail – he says he was tortured, beaten and left hanging from the wrists. Ms Bouchar, who says she was chained to a wall and deprived of food for five days, was only released after she had given birth.

What is the British link?

Papers unearthed in Tripoli show the extraordinary efforts made by the Blair Government to bring Gaddafi in from the cold. One letter, allegedly sent in March 2004 from Sir Mark Allen, the former MI6 director of counter terrorism, to Moussa Koussa, the former Libyan foreign minister, is said to pass on thanks for helping to arrange Tony Blair’s recent visit to Gaddafi. It adds: “Most importantly, I congratulate you on the safe arrival of Abu Abd Allah Sadiq [an alternative name for Belhadj] “This was the least we could do for you and for Libya to demonstrate the remarkable relationship we have built.”

Why is Straw being sued?

The Sunday Times this week quoted “well-placed sources” as alleging that Mr Straw did approve the rendition operation.Mr Straw has always denied approving unlawful rendition.