Two Libyans who claim Britain's complicity in their torture by Moamer Gaddafi's regime are taking legal action against former British foreign secretary Jack Straw, their lawyers said Wednesday.

Abdelhakim Belhaj, who became Tripoli's military commander after the Libyan leader was ousted in last year's revolution, and fellow Gaddafi opponent Sami al-Saadi claim British involvement in their illegal rendition in 2004.

Their lawyers said legal papers have been served on Straw following media reports that he approved the men's capture and transfer to Gaddafi's Libya while he was foreign secretary under Tony Blair's Labour government.

"The civil action is against Mr Straw personally and seeks his response to allegations that he was complicit in torture and misfeasance in public office," Leigh Day & Co solicitors said in a statement.

"It seeks to examine his exact role in the rendition of Mr Al Saadi and Mr Belhaj as well as claiming damages from him personally for the trauma involved.

"However, Mr Belhaj has consistently made clear that his predominant aim in taking legal action is to seek an apology for what took place and for the truth to be known."

Straw told the BBC he was unable to comment on the legal action because of the ongoing police investigation into the case.

Belhaj and Saadi are already suing the British government and Mark Allen, the former counter-terrorism director of spy agency MI6, after documents emerged suggesting his direct involvement in their rendition.

Files unearthed from Gaddafi's archives after his fall last year said Belhaj was captured by the CIA in Bangkok in 2004 and with British help was forcibly returned to Libya, where he was jailed in the notorious Abu Salim prison.

Saadi meanwhile claims British agents helped detain him in Hong Kong in 2004 and return him to Libya, where he was subjected to years of torture.

"When scandals like this break, the political paymasters almost never face the music. For once, there's a chance things might be different," said Cori Crider, legal director of campaigning charity Reprieve.