It sounds great in the movies, but when you try to do it, it’s not that easy,” a former intelligence official said. “Where do you base them? What do they look like? Are they going to be sitting around at headquarters on 24-hour alert waiting to be called?

The interrogation and detention regime implemented by the U.S. resulted in the deaths of over 100 detainees in U.S. custody

Defenders of these techniques have claimed that they got Abu Zubaydah to give up information leading to the capture of Ramzi bin al-Shibh, a top aide to Khalid Shaikh Mohammed, and Mr. Padilla. This is false. The information that led to Mr. Shibh’s capture came primarily from a different terrorist operative who was interviewed using traditional methods. As for Mr. Padilla, the dates just don’t add up: the harsh techniques were approved in the memo of August 2002, Mr. Padilla had been arrested that May.

CIA interrogation techniques used on al-Qaeda suspects "constituted torture", according to a leaked report by the international Red Cross.

The 25 lines edited out of the court papers contained details of how Mr Mohamed's genitals were sliced with a scalpel and other torture methods so extreme that waterboarding, the controversial technique of simulated drowning, "is very far down the list of things they did," the official said.

Another source familiar with the case said: "British intelligence officers knew about the torture and didn't do anything about it. They supplied information to the Americans and the Moroccans. They supplied questions, they supplied photographs. There is evidence of all of that."

David Davis, the former shadow home secretary who first highlighted the case, said: "What has become clear is that the information being held back is not protecting the American government who have made a clean breast of their involvement in torture, but the British government, where at least two cabinet ministers have denied any complicity whatsoever.