Instead, after almost two weeks in detention at the airport under questionable conditions, Hong Kong authorities handcuffed Saadi and his wife before forcing them and their four young children, all aged under 14, aboard a Libya-bound plane.

When the plane doors opened, they were greeted by Gaddafi's agents. Saadi's wife screamed, fearing she would be murdered, and one of Saadi's young daughters fainted from fear.

Saadi, a diabetic, also went into shock and fainted on the flight after his blood sugar reached dangerous levels.

In a statement issued through the London-based human rights law firm Reprieve, Saadi, also known as Abu Munthir, described his despair when he realised what was happening.

'My first feeling when the door to the rendition plane opened in Hong Kong and I saw the Libyans was a mixture of sadness and anger,' he said. 'I was extremely upset to see my wife screaming while handcuffed.

'My daughter also lost consciousness at the time. The British had guaranteed my safety. It never occurred to me they would deliberately send anyone to Gaddafi's torture chambers.'

The family's ordeal started around March 15, 2004, when they first arrived in Hong Kong.

The family had been living in Guangzhou for about a year, but Saadi feared for their safety and sought to return to the UK where he had lived during the 1990s.

The family were told by a UK intermediary to fly to Hong Kong, where Saadi would be formally interviewed at the British consulate, after which his request for political asylum would be granted. But when they arrived at the airport, the entire family was detained for passport violations. They were apparently travelling on a false French passport.

During their detention, they were denied proper beds, medical care or even a reason for their continued incarceration by the Hong Kong authorities. Saadi pleaded with the city's officials for an explanation but was kept in the dark, according to Cori Crider, one of his lawyers who is mounting legal action against the UK government.

'They refused to give him any reason. Indeed, he asked, and a very senior Hong Kong official smiled and said he couldn't say,' Crider said.

'Initially, [Hong Kong authorities] told him he was going to go back to China and at one moment, seemed to be sending the family on a regular commercial flight to China.

'But at the last moment, they pulled everyone off the plane and held them for a few more days.'

Last month, Saadi's rendition case received international attention after secret CIA documents were uncovered from the abandoned Tripoli office of Gaddafi's intelligence chief.

The classified papers detailed how the Hong Kong government demanded assurances that Saadi and his family would not be tortured or killed as a result of the rendition.

When Saadi arrived in Tripoli, he spent the next six years in jail. In three years in Tajoura prison he was tortured, beaten and electrocuted.

He also said that during his detention in Tripoli, CIA agents quizzed him about alleged links to al-Qaeda.

Saadi, represented by Reprieve and UK law firm Leigh Day, launched legal action last week against the British intelligence agencies MI5 and MI6, the attorney general, the Foreign Office and the Home Office.

It cites their 'alleged complicity in his extraordinary rendition from Hong Kong to Tripoli' and his subsequent 'unlawful detention, torture, inhuman and degrading treatment, batteries and assaults perpetrated by the Libyan authorities'.

Saadi, living in Libya now with his family, was freed from the Abu Salim jail on August 23 this year after rebels stormed the site. He was carried out, weighing just 44kg.