LONDON -- Former Guantanamo Bay detainees and their lawyers said Thursday they won't cooperate with an inquiry into Britain's conduct as it pursued terrorism suspects in the aftermath of the Sept. 11, 2001 attacks on the United States, unless they are able to question spies and other witnesses.
Prime Minister David Cameron has ordered a sweeping investigation into allegations that British officials may have colluded in the mistreatment of detainees held overseas, following a series of accusations leveled by one-time suspects.
The inquiry disclosed last month that most intelligence officials would appear only in private and that the government will retain final say on making sensitive documents public.
In a joint letter sent to the inquiry's legal chief, lawyers complained that the rules mean ex-detainees and their legal representatives won't have the chance to question spies or government ministers.
Human rights groups said in a second letter that the inquiry won't be independent enough because the final decision on public disclosure of evidence will be made by Britain's Cabinet Office.
Both the lawyers for ex-detainees and 10 civil liberties groups have told the inquiry that they won't submit evidence or attend sessions, unless the panel changes its procedures.
The retired judge leading the inquiry won't open sessions until police complete a criminal investigation into allegations that an officer with Britain's overseas intelligence agency, MI6, was complicit in the mistreatment of detainees overseas.
In their letter, lawyers complained that detainees and their legal representatives "will not be able to ask questions, or see or hear the key evidence which is to be considered only in secret session."
Kevin Laue, a lawyer with human rights group Redress -- which signed one of the critical letters -- said it hopes the inquiry will agree to alter its arrangements, allowing detainees to present the evidence that they allege shows how Britain colluded in torture.
"The door is open and we would hope that there will be changes to the protocols to make it possible for a proper inquiry," Laue said.
In a statement, the inquiry said it had no plans to change its rules and that for lawyers, detainees and other groups the hearings would be "the only opportunity for them to give evidence to an independent inquiry."
The inquiry panel won't seek evidence from the U.S. or other foreign allies, disappointing campaigners who had hoped the study would be the most thorough yet of alleged murky practices by Western military and intelligence officials.
Last year, Britain paid millions of pounds (dollars) in settlements to 16 former Guantanamo Bay detainees who alleged U.K. complicity in their harsh treatment overseas, though the government did not admit any liability.