In themselves, the revelations in the Foreign Office document contained little that was not already known from previous disclosures by the Central Intelligence Agency about the so-called stress techniques used by American interrogators while questioning terrorist suspects after the Sept. 11, 2001, attacks in the United States.

What was starkly new, however, was the Foreign Office’s conclusion that the treatment Mr. Mohamed endured, had it been carried out under the authority of British officials, would have breached international treaties banning torture. It was the first time that Britain has been so blunt about its disapproval of the interrogation techniques approved by former President George W. Bush and curtailed last year by President Obama.

“Although it is not necessary for us to categorize the treatment reported, it could readily be contended to be at the very least cruel, inhuman and degrading treatment by the United States authorities,” the document posted on the Foreign Office Web site said.

The court order, issued by a three-judge panel, could have been further appealed by the Foreign Office. Mr. Miliband told the Commons that the government had decided not to pursue the case because the judges had reaffirmed the so-called control principle governing intelligence-sharing relationships.

That rule, as Mr. Miliband put it, holds “that intelligence material provided by one country to another remains confidential to the country that provided it, and that it will never be disclosed directly or indirectly by the receiving country, without the permission of the provider of the information.”

Mr. Miliband said that he had discussed the case with Mrs. Clinton by telephone on Tuesday night, and that Britain was pledged to “work carefully with the United States in the weeks ahead to discuss the judgment and its implications” for future intelligence sharing. In response to opposition questioners, he hinted at continuing American disquiet, saying that it was “too early to come to this House and say that this will have no effect” on American-British intelligence relationships.

The foreign secretary said that what had persuaded Britain not to mount a further appeal and by implication, what had opened the door to American agreement that the secret information could be released  was a United States district court ruling in December in Washington, D.C., which he said had “made a finding of fact” in respect to Mr. Mohamed’s allegations of mistreatment that closely paralleled what was revealed in the Foreign Office document.

Mr. Miliband was at pains to say that the government acknowledged that Mr. Mohamed had been right to allege that he had been mistreated. In fact, he said, “this judgment is not evidence that the system is broken; rather it is evidence that the system is working and the full force of the law is available when citizens believe they have just cause.”