Series of allegations that finally forced Brown to act

Brown asks ISC to look at interrogation policy again
Detainees claimed MI5 collusion as early as 2005

If we are to believe Peter Wright, the former MI5 officer and author of Spycatcher, new recruits to the security service are quickly expected to take to heart its 11th commandment: "Thou shalt not get caught." Today, however, as the result of the work of a small group of lawyers, journalists and parliamentarians, it is beginning to look as though MI5 has been found guilty of breaking its own rule: its involvement in torture is becoming clear.

While the prime minister declared his complete faith in the security service in the Commons yesterday, his decision to ask the Intelligence and Security Committee (ISC) to look again at the policy governing the interrogation of detainees will be seized upon by campaigners as an acknowledgement that something has gone disastrously, dangerously wrong.

It emerged on Tuesday evening that the ISC had already bowed to pressure to examine the policy while sitting in secret. In a statement, it said: "We have taken further, in-depth evidence from the intelligence and security agencies, and the foreign and commonwealth office. We have today reported our findings on a number of aspects - including the issues raised about the policies that the UK security and intelligence agencies have followed and should follow - and made recommendations to the prime minister."

The ISC did not say what those recommendations are, and it is unclear how far its chair, Kim Howells, felt able to offer overt criticism of what has happened in the past, as he was foreign office minister with responsibility for counter-terrorism during much of the time that the alleged abuses took place.

Reprieve, the legal charity, said asking the ISC to examine what has gone wrong was "a textbook case of the fox guarding the hen house". Nevertheless, whatever the ISC said to Brown appears to have prompted him to ask the committee to look again at the interrogation policy, "to reassure ourselves that everything has been done to ensure that our practices are in line with UK and international law".

It is now apparent that a policy governing the interrogation of the enormous number of people rounded up in the early days of the so-called war on terror was drawn up by lawyers, intelligence officers and figures in government, and that it has been gradually developed over time. This policy, while not "encouraging or condoning torture", to use the government's words, resulted in British citizens and residents, and others, being tortured. Some human rights campaigners say the policy has been used to facilitate torture.

An MI5 officer who interrogated the British resident Binyam Mohamed in Pakistan in 2002 referred to this policy during a case brought to the high court on Mohamed's behalf last year. The officer, identified only as Witness B, said: "I was aware that the general question of interviewing detainees had been discussed at length by security service management legal advisers and government, and I acted in this case, as in others, under the strong impression that it was considered to be proper and lawful." Mohamed was tortured both before and after the MI5 officer interrogated him.

There had been signs as early as 2005 that MI5 had become involved in torture, when a man from Luton, Salahuddin Amin, was deported to the UK from Pakistan, where he had been held illegally for 10 months by the country's notorious Inter-Services Intelligence directorate (ISI). Amin, now 34, had been repeatedly questioned by two MI5 officers while in ISI detention, and said he was beaten, whipped and threatened by the ISI before most of these sessions. A judge later ruled his treatment had been "physically oppressive" but that it fell short of torture.

There were others who spoke of their torture in Pakistan and Egypt. Human Rights Watch, the New York-based NGO, said that its researchers have spoken to the Pakistani intelligence officers responsible for the torture of Zeeshan Siddiqui, 28, from Hillingdon, west London, and reported that those men said British intelligence officers in Pakistan were fully aware of what was happening to Siddiqui.

Many of these matters will be the subject of litigation that is expected to keep Britain's civil courts and the European courts busy for many years. And some lawyers are predicting that the public will learn just how closely MI5 had become to overseas intelligence agencies whose use of torture has been well documented.