At Foreign Office Questions recently the minister responsible for Middle East affairs snapped. MPs from all sides were pressing for answers about "extraordinary rendition" and were unsatisfied with the stock reply from Kim Howells: "We have no knowledge of this and we have received no requests from the Bush government."
Challenged for the umpteenth time, Howells let his righteous indignation show. "The government are opposed to torture," he said. "They do not torture anyone, nor would we ever, ever put up with any other administration torturing individuals."
This blustering response was entirely disingenuous, the New Statesman can now demonstrate. It does not begin to describe the reality, which is set out in a secret, high- level memo - obtained by this magazine - that passed from the Foreign Office to Downing Street last month. For the truth is that the government is involved in a cover-up, not so much of what it knows about this shady business, but what it doesn't know. The one thing it is pretty sure about, however, is that if it has happened, and if Britain had a role, then the government has broken the law.
An honest answer from Howells might have looked like this: "The government has no idea whether renditions have taken place in the past few years and nor do we know whether any requests have been made for British co-operation. If they have they are almost certainly illegal, but we have decided to back the US government anyway because it has promised that it would not allow anyone to be tortured - though it doesn't mind a bit of cruel, inhuman and degrading treatment."
Had he wished to be even more frank, the minister might have added: "We are terrified about this issue and what it might do to us, and so we are desperately trying to distract attention from it by talking endlessly about the global threat from terrorists."
The scandal of extraordinary rendition, the practice of taking terror suspects to be questioned in countries where interrogation methods may be used that would not be legal in the US, has been brewing for 18 months, since Stephen Grey revealed the scope of the operations in these pages. It reached boiling point late last year when a critical mass of evidence was achieved, involving flight details of CIA planes - often through European countries, including Britain - and testimony from ex-prisoners.
As Tony Blair prepared to face Commons questions about British involvement in early December, his officials asked the Foreign Office for a briefing document. The resulting memo, signed by Irfan Siddiq, a private secretary at the Foreign Office, and addressed to Grace Cassy, assistant private secretary at No 10 Downing Street, paints an astonishing picture.
Extraordinary rendition, it declares bluntly, "is almost certainly illegal", and if Britain co-operated with an illegal act of this kind, "such an act would also be illegal".
Remarkably, however, the Foreign Office doesn't know whether this has happened. As of early December it had not been able "to complete the substantial research required to establish what has happened since 1997". The Home Office, too, "are urgently examining their files", as are the Ministry of Defence and the security service.
Two possible cases had so far been identified, though it wasn't yet clear whether these were illegal, but "the papers we have unearthed so far suggest there could be more". While the paperchase goes on, therefore, a shocking admission is made: "We now cannot say that we have received no such requests for the use of UK territory or air space for 'Extraordinary Rendition'."
The document addresses the specific question: "How do we know whether those our armed forces have helped to capture in Iraq or Afghanistan have subsequently been sent to interrogation centres?" And the answer is: "We have no mechanism for establishing this, though we would not ourselves question such detainees while they were in such facilities."
Against this background of ignorance and a distinct possibility that the law has been broken, the memo offers advice to Blair on how to deal with the issue in public. "We should try to avoid getting drawn on detail," it says, and "try to move the debate on . . . underlining all the time the strong counter-terrorist rationale for close co-operation with the US".
And the memo places revealing stress on the need to follow the precise wording of statements by the US secretary of state, Condoleezza Rice, who admitted rendition was US policy but denied that the US practised or permitted torture. When she used the word "torture", the memo makes clear, she probably had in mind a particular definition of the term which did not include cruel, inhuman or degrading treatment.
Here, then, is the explanation for the frustration shown by Kim Howells: MPs were refusing to allow him to play out the government's deliberate, considered strategy of deflecting public attention from this explosive issue. And in this light the Prime Minister's response in December to the then Liberal Democrat leader Charles Kennedy's questions is instructive. At best it is sophistry, at worst dissimulation.
"Let me draw a very clear distinction indeed," he said, "between the idea of suspects being taken from one country to another and any sense whatever that ourselves, the United States or anyone condones the use of torture. Torture cannot be justified in any set of circumstances at all.
"The practice of rendition as described by Secretary of State Condoleezza Rice has been American policy for many years. We have not had such a situation here, but that has been American policy for many, many years. However, it must be applied in accordance with international conventions, and I accept entirely Secretary of State Rice's assurance that it has been."
Only the concentration on torture and on the assurances given by Rice allow Blair to sound categorical. Britain's legal position on what constitutes torture, the secret memo makes clear, is different from the American one. The shocking reality that Blair concealed was that his government had no idea whether British territory or airspace had been used for rendition, extraordinary or otherwise, at any time since 1998.
The leaked document contains details of two requests from 1998 which help paint a picture of what these flights are used for. In one, Mohammed al-Owhali, a Saudi suspect in the US embassy bombing in Kenya, was "rendered" to the US with the approval of the then home secretary, Jack Straw. His route was switched at the last minute from Prestwick in Scotland, where many of the secret flights have been logged, to Stansted.
In a second case, the request was refused because the US intended to transport a detainee to Egypt, a country that is known to practise torture. The Foreign Office official states: "From the information we have at the moment, we are not sure in either case whether the individual's transfer from the country in which he was detained was extra-legal."
Human-rights groups have long demanded that the government come clean about renditions, and the memo offers a new and unexpected explanation for the official coyness: ministers have little idea of what has been done by the American government on sovereign British territory in the name of the war on terror.
Several questions arise: was the US given the nod to do what it wanted, with Britain keeping no systematic record? Why did it take seven years for the government to ask itself questions about the legality of all this? Why is a diplomat providing advice for spinning the story and "moving it on"? One thing is clear: the government failed to ask our US allies the most basic questions about individuals passing through our territory. And now it turns out it may not even have the "mechanism" to find the truth.
With further revelations about CIA flights to Scotland emerging, it is unlikely that the government will be able to "move the debate on" just yet. A criminal investigation is being carried out by the chief of Greater Manchester Police, Michael Todd, and several parliamentary groups, including the foreign affairs committee, are looking into the issue. None of these is likely to pierce US government secrecy, but they may yet uncover the full scale of the government's complacency and ignorance.
To see the full document go to our website at: www.newstatesman.com/rendition