Binyam Mohamed is finally returning to Britain more than seven years after he left on an ill-fated trip to Afghanistan.
The 30-year-old Guantanamo Bay detainee was arrested in Pakistan in April 2002 as he tried to fly back to London, and has been held without charge by the Pakistani and US authorities ever since.
His case has raised allegations that MI5 agents were complicit in the torture of suspects, and that the British and American governments conspired to cover up evidence of abuse.
Ethiopian-born Mr Mohamed was a teenager when he came to the UK seeking asylum in 1994.
He was eventually granted leave to remain, although he was never given British citizenship.
During his years in Britain he worked as a caretaker in Kensington, west London, studied electrical engineering and converted to Islam.
The turning point in his life came in June 2001, when he decided to travel to Pakistan and then on to Afghanistan.
What Mr Mohamed did in Afghanistan is a matter of dispute.
He insists he only went there to get away from a bad circle of acquaintances in London who had led him into drug addiction and to see for himself how the Taliban's strict Islamic regime worked.
But the US military has alleged that he received paramilitary training at al Qaida's al Farouq training camp, fought for the Taliban and plotted detonating a radioactive "dirty bomb" in America.
In early summer 2001 he allegedly attended a lecture in which Osama Bin Laden warned that "something big is going to happen in the future" - an apparent reference to the upcoming September 11 attacks on the US.
A US military charge sheet alleges he was selected by al Qaida for a "specialised terrorist mission" because of his education, fluency in English and refugee status in the UK.
Mr Mohamed was accused of conspiring with American Muslim convert Jose Padilla to build a dirty bomb to set off in a public place in the US.
The British resident denies all the allegations, and says he only made confessions after suffering months of physical and psychological torture.
Mr Mohamed was detained by the Pakistani authorities at Karachi Airport on April 10, 2002 as he tried to return to Britain on a false passport.
He alleges he was tortured by Pakistani agents, who hung him for a week by a leather strap around his wrists so he could barely stand, only allowing him down twice a day to go to the toilet.
According to his account, two MI5 officers visited him in Pakistan, one of whom told him he would be taken to the Middle East and "tortured by the Arabs".
In July 2002 Mr Mohamed was handed over to US agents and flown to Morocco on a secret CIA rendition flight, his lawyers say.
Here he was allegedly repeatedly tortured, including having his penis cut with a scalpel.
He said his interrogators mentioned details about his personal life in the UK - including his education and the names of his kick-boxing instructor and friends - which must have come from British intelligence.
After 18 months in Morocco Mr Mohamed was flown to Afghanistan, where he signed a confession that he later claimed was extracted under duress.
In September 2004 he was moved again to the US military detention centre at Guantanamo Bay in Cuba, where he was to remain for more than four years.
In 2005 he was charged with conspiracy to plan terror attacks in America, but all charges against him were dropped in October last year.
After years of campaigning by his supporters to have him either charged in a civilian court or released, Mr Mohamed was told unofficially in December that he was to be freed after the US administration of George Bush left office.
Frustrated by yet another delay, he went on hunger strike from January 5 until February 11, when a member of his legal team persuaded him that his release really was imminent.
Now he is being freed from Guantanamo Bay, Mr Mohamed hopes to retreat from the world.
"He wants to go somewhere extremely quiet and have nothing to do with anyone," his lawyer, Clive Stafford Smith, said.Reuse content