Lawyers for a prominent ex-Libyan rebel who is suing Britain over its alleged role in his 2004 rendition said Friday he has withdrawn his cooperation for a UK government commissioned inquiry into abuses during its pursuit of terrorism suspects.
Tripoli's military council commander Abdel-Hakim Belhaj had been scheduled to contribute to the investigation after British Prime Minister David Cameron promised it would consider whether ties between the British and Libyan security services became too cozy during Moammar Gadhafi's rule.
Belhaj, a former fighter in the Libyan Islamic Fighting Group _ a militant organization that long opposed Gadhafi _ and among Libya's most prominent Islamist figures, claims both British and U.S. intelligence may have played a role in his 2004 detention in Bangkok and transfer to Tripoli.
Documents uncovered during the fall of Tripoli disclosed the close working ties between Gadhafi's spies and Western intelligence officials.
Lawyers Leigh Day & Co said Belhaj wouldn't cooperate with the U.K. inquiry as he now believed it had insufficient powers to "get to the truth of Britain's involvement" in abuses during the so-called "war on terror."
Several ex-Guantanamo Bay detainees _ including those paid millions of pounds (dollars) in settlements by Britain over allegations the U.K. was complicit in their harsh treatment _ have previously said similar concerns mean they won't take part.
In 2010, Cameron asked retired appeal court judge Peter Gibson to carry out a sweeping examination of Britain's conduct in the years after the Sept. 11, 2001, attacks on the United States.
Foreign Secretary William Hague has said the inquiry is necessary to "clear the stain from our reputation as a country."
Hearings in Gibson's inquiry have been delayed until police conclude investigations opened in 2009 into allegations an officer with the country's MI6 overseas intelligence agency was complicit in the mistreatment of a non-British citizen.
Rights groups have repeatedly complained that the government _ not the inquiry _ will have the final say on what evidence is made public. The panel will hold some sessions in private to hear evidence from intelligence officials and review some secret documents the government may block from being publicly released.
In a joint letter to Cameron, several civil rights campaign groups _ including Amnesty International U.K., Liberty and Reprieve _ legal experts and two former United Nations special rapporteurs on torture urged Britain to review the panel's powers.
"There is growing concern that the powers currently given to the inquiry are seriously deficient and that it will be unable to properly fulfill the U.K.'s human rights obligations," said the letter, sent Friday.
"Without substantial changes, it will not get to the truth of Britain's involvement or ensure such abuses do not occur again."
Clare Algar, executive director of Reprieve, said campaigners hoped Cameron "sees sense and gives this inquiry the clout it needs to really make a difference."
"An inquiry as inadequate as the one currently established risks a whitewash that will do more harm than good _ not least in terms of restoring public trust and Britain's reputation around the world," she said.
In a statement, the inquiry insisted it would "deliver a robust" examination of the issues Cameron asked it to address.