Written guidelines for British secret agents on how to interrogate prisoners held overseas will face a legal challenge in the courts, a human rights groups has announced.
Reprieve, which represents Binyam Mohamed and several other former Guantanamo Bay detainees, is to launch a judicial review of the code of practice used by MI5 and MI6.
The charity claims the unpublished 2002 and 2004 versions of the policy were illegal because they condoned complicity in torture.
Ministers have maintained that the UK neither practices nor condones torture or mistreatment of prisoners.
But Reprieve accused the Government of making "broad assertions" that its policy is legal while failing to address specific allegations.
Evidence from 10 cases suggests the policy could have unlawfully endorsed complicity in torture, it claims.
Prime Minister Gordon Brown is yet to fulfil a pledge made last year to release the latest version of the guidance.
Reprieve director Clive Stafford Smith said: "Advice given to agents cannot sensibly be deemed 'classified', as disclosing legal advice hardly betrays a national secret. Rather, depending on what the policy was, it exposes those who sanctioned the advice to immense embarrassment.
"Equally, it cannot take a year to come up with new advice - we could have written it for them in an afternoon.
"Agents in the field are still, apparently, required to rely on the 2004 policy. Meanwhile, the Government is playing for time here, hoping that the issue can be punted past the election to the next Parliament."
