Abdel Hakim Belhaj said he and his pregnant wife were detained in Bangkok in 2004, then transferred to Abu Salim jail, Tripoli.
He said he was held there for six years and often tortured. Belhaj, who is now the military commander of Tripoli, worked with Nato as one of the leaders of the forces that helped overthrow Moammar Gadhafi.
But he claims that during his time in prison he was interrogated by agents from countries including the UK and US as a suspected al-Qaeda sympathiser.
Belhaj said he was beaten, hung from walls and cut off from human contact and daylight, before being sentenced to death during a 15-minute trial.
He said his wife was also imprisoned in Libya for four months and released just before she gave birth, the BBC reported.
They had been living in exile in Beijing, China after Belhaj had led a low-level insurgency against Gadhafi.
In September, Belhaj told the BBC that after he was captured he was tortured by the CIA and Gadhafi forces. “What happened to me was illegal and it deserves an apology,” he said.
A spokeswoman for the legal campaign group Reprieve said the UK government’s failure to issue an apology had led Belhaj’s lawyers, from Leigh Day & Co, to send a letter initiating legal action. The government now has six months to respond, she said.
