A former Libyan rebel commander has won the legal right to sue the UK for damages over years of torture he says he endured at the hands of Muammar Gaddafi's henchmen after being illegally handed to Libya by British and US authorities.

The UK's Court of Appeal ruled on Thursday that Abdel Hakim Belhaj, who helped topple Gaddafi in 2011, could sue the government over his claim that Britain conspired with the CIA in his "rendition" to Libya.

The case could pave the way for similar legal action against the British government in similar torture or rendition cases.

"The allegations in this case, although they are only allegations, are of particularly grave violations of human rights," the court ruling said.

Libya: Renditions

"The stark reality is that unless the English courts are able to exercise jurisdiction in this case, these very grave allegations against the executive will never be subjected to judicial investigation."

A spokesman for Britain's Foreign Office declined to comment on the court ruling.

Belhaj, who is now leader of the Libyan al-Watan Party, says he and his pregnant wife were abducted by CIA agents in Thailand in 2004 and then transferred to Tripoli with the help of British security officials.

After the fall of Gaddafi, documents were discovered indicating British officials had been in contact with Libya's former spy chief Moussa Koussa over Belhadj.

Belhadj says he was originally detained in China, before being transferred to Malaysia and then moved to a CIA "black site" in Thailand.

He says he was then flown via the British island of Diego Garcia in the Indian Ocean to Tripoli.

As a long-standing enemy of Gaddafi, he was imprisoned and tortured for six years while his wife was also mistreated during her four-month incarceration.

The files unearthed from Gaddafi's archives after his fall suggest Belhadj was captured due to a British tip-off after he initially made an attempt to seek asylum in the UK.

'Deal in the desert'

Britain and the US had been keen to build relations with Gaddafi at the time, following the Libyan leader's 2003 pledge to give up sponsoring terrorism and to end his country's chemical and nuclear weapons programmes.

In 2004, British Prime Minister Tony Blair met Gaddafi in what was described as the "deal in the desert," bringing Libya back into the international fold.

"Our part of the 'deal in the desert' - the kidnap, the secret CIA jail, the torture chamber in Tripoli - is as fresh and as painful for us as if it happened yesterday," Belhadj said in a statement.

"We never dreamed Britain would have conspired in such a thing until we saw the proof with our own eyes, right there in Moussa Koussa's dusty binders."

In 2011, Belhaj began legal action against former British Foreign Secretary Jack Straw, Britain's MI5 and MI6 spy agencies, a former intelligence chief, and relevant government departments, but last year a High Court judge ruled English courts could not hear the case.

British ministers have repeatedly denied any knowledge of sending anyone to face torture abroad, and there have also been warnings that exposing secret intelligence material in court cases might damage relations with the US.

Source: Agencies