The head of the civil service will have the final say on which material in the detainee inquiry investigating torture allegations is made public, it has emerged.
Campaigning groups expressed concern after the protocol for judge Sir Peter Gibson's inquiry into allegations of British complicity in torture stated Cabinet secretary Sir Gus O'Donnell will have the final word.
The definition of evidence which will remain classified covers anything which would in any way breach an 'understanding' between the UK and its allies.
If a British agent watched Americans abusing a prisoner, Reprieve argued, the inquiry will determine that the agreement was that they were only present on the 'understanding' that nothing should be made public.
"Given that the essence of British complicity involves working with the US on torture and rendition, the exception to publicity swallows the rule," it stated.
Civil liberties group Liberty's director, Shami Chakrabarti, said she feared the probe looked more like a "secret internal review" than a fully-fledged inquiry.
"The new government won wide praise for promising a public inquiry but as always the devil is in the detail," she said.
"Today's disappointing announcement suggests ministers, not independent judges, will decide what the public is entitled to know. It is very hard to see the point of wasting public money on such a sham."
Clive Stafford-Smith, director of Reprieve, said the inquiry was a "whitewash".
"National security continues to be conflated with political embarrassment in this process," he argued.
"This is meant to be an inquiry into British complicity into torture and rendition, almost all of which was complicity with the Americans. Yet these terms give America a veto on much of what should be public."
Detainees will not be allowed to know what evidence is given by the security services about the agencies' involvement in torture and unlawful rendition, solicitor Louise Christian said.
"It is shameful that the basis on which this inquiry has been set up casts such doubt on the commitment of the government to investigate the security services properly," she commented.
Gareth Peirce, solicitor to eleven current or former Guantanamo Bay detainees, said the government was offering a "wholly inadequate response to the gravest of state crimes, torture".
"Ironically the Ministry of Defence exposed the torture of Baha Mousa by its personnel at a time of war to public scrutiny," he said.
"The intelligence services, in contrast, are being allowed to hide. History shows it is, above all, the vice of secrecy that ensures that the elimination of torture can never be achieved."
The inquiry has not yet begun its work because the Metropolitan police continues to work on investigations into "related matters". It is currently conducting preparatory work.