We're soon to be told, officially, what guidance is given to British intelligence agents when they're questioning detainees held abroad. Are they advised, if there's any unpleasantness afoot, to leave the room? To shut their eyes tight and cover their ears? To report malfeasance to the nearest police station or passing UN human rights' rapporteur?
It's the latest twist in the extraordinarily tangled tale of America's War on Terror, torture, and the secret "rendition" of prisoners from country to country by the CIA.
Immediately on taking office, Barack Obama was ostensibly able to start wiping clean the slate. As the head of a new administration, the president could deny responsibility for what had gone before. Gordon Brown, lumped with Tony Blair's legacy and own part in it, has no such advantage.
Which brings us back to the the case of Binyam Mohamed, late of Guantanamo Bay and various hell hole prison cells in Afghanistan, Pakistan and, Morocco. Binyam is in many ways the personification of the War on Terror and all its ambiguities. He is both an alleged perpetrator and a victim. He was supposedly bent on destroying Western democracy yet the west denied him civil, legal and democratic rights and then allegedly did far worse, putting him to torture.
Binyam was arrested at Karachi airport trying to leave Pakistan with a false passport in April 2002, having fled from Afghanistan and the American invasion. He says he'd gone to Afghanistan pre 9/11 to get off drugs and investigate Islam. While such a claim may be met with scepticism it remains wholly plausible: many ardent converts will turn to religion after struggling with an addiction or personal trauma.
It is likely, however, that it will have been a radical and fundamentalist Islam that Binyam was following up: Afghanistan was under the iron rule of the Taliban. So Binyam's contacts in the UK, where he'd first found God, would have been of considerable interest to MI5. At this time - early 2002 - the shoe bomber, Londoner Richard Reid (former drug addict and recent convert to hard line Islam), had just been prevented from blowing up a Transatlantic airliner.
Where things get sticky for the British government - the current British government - is when Binyam is detained in Pakistan, under CIA control, and is interviewed by an MI5 officer. The officer, we know from various telegrams and reports revealed on Newsnight, warns Binyam to cooperate with his captors if he knows what's good for him. On May 17 2002 the officer reported as much back to London.
During this period, Binyam says, he was regularly being strapped to the ceiling by Pakistani interrogators. He suggests the MI5 agent must have been aware of this treatment.
Later, we now know, Binyam was spirited away to Morocco. It's here, he says, over eighteen months the torture intensified while he was asked questions supplied to the CIA by MI5. The information ranged from the identity and nature of his kick boxing instructor in North Kensington to his exam results; he was also shown "hundreds and hundreds" of photographs of Muslim men based in the UK and asked who he recognised and what he knew of them.
This information, Binyam and his lawyers believe, can only have been provided by the UK with the implication that Britain was at the very least complicit in Binyam's treatment. And we know MI5 was aware he had been "disappeared" by the CIA because on October 25, 2002 at MI5 headquarters in Thames House, London, they asked the Americans where Binyam had been taken and were told in effect to mind their own business.
British officials, apparently having decided they could do no more to locate Binyam Mohamed and ask him questions directly, then asked the CIA to put some further questions on their behalf. They continued to provide information for their U.S. colleagues to put to Binyam - wherever he was and under whatever conditions he was being held - over the following weeks.
Does this make Britain complicit in Binyam Mohamed's treatment? Does it suggest they've colluded in torture? For all their bluster about opposing torture and rendition, no minister has so far denied complicity. This may be significant.
Meanwhile Gordon Brown, saying he wants to restore public faith in the security services, has asked the Commons Intelligence and Security Committee to help draw up new guidelines on interrogation "in order to have systems that are robust". The Commons Intelligence and Security Committee, you may note, are appointed by and report directly to the Prime Minister and are frequently criticised for their secrecy and refusal to discuss their work.
Earlier this year High Court judges suggested the committee had been misled by intelligence chiefs over Binyam Mohamed and that they should reopen their investigation into his case. Now the committee has announced it has taken the judges' advice.
Barack Obama has announced the end of the War on Terror, an abstract noun that was as inane as it was counter-productive. No more the concept of "enemy combatants" or "enhanced interrogation techniques". The fall out, however, will be with us for a long while yet.