A senior Democrat on Capitol Hill has mounted a fresh challenge to Britain’s insistence that its relations with US intelligence agencies would be threatened by disclosing evidence of torture.

Bill Delahunt said that the Obama Administration must clarify its position over the release of documents detailing the treatment of Binyam Mohammed, a former British resident currently on hunger strike in Guantanamo Bay.

Last week David Miliband persuaded the High Court to suppress the publication of evidence that Mr Mohammed was subjected to cruel, degrading or inhuman treatment by US agents during interrogation in Morocco and Afghanistan. According to some accounts, British officials were complicit in his incarceration and torture that included beatings, being scalded with boiling water and having his penis cut by a razor blade.

The Foreign Secretary signed a public interest immunity certificate warning judges that releasing such material would damage America’s national security and “could harm existing intelligence-sharing arrangements between our two governments”. Mr Mohammed’s lawyers will make another effort today to overturn the High Court’s ruling.

Mr Delahunt, chairman of the House of Representatives human rights sub-committee, told The Times he was writing to Eric Holder, the Attorney-General, with an urgent request to review the case.

“There seems to be no valid national security reason that would prevent full disclosure,” he said. “I know the President has concerns about this kind of affair and expressed a desire to be transparent. I believe he will act in good faith.”

Although Mr Miliband later stressed in Parliament that no direct threat to sever intelligence ties had been received from Washington, he said the Obama Administration was expected to uphold a long-established principle by which countries maintain control over such information.

“I am not going to join a lobbying campaign against the American Government for this decision,” he added, underlining the Government’s abhorrence of torture.

The US State Department last week expressed its gratitude to Britain “for its continued commitment to protecting sensitive national security information and to preserve our longstanding intelligence-sharing relationship”.

Mr Delahunt dismissed this as a “bland statement” and added: “The whole issue needs to be addressed at a much higher level. To restore the confidence of the world and the American people in the integrity of our Government, it’s absolutely essential to have a catharsis. We have made mistakes and we must acknowledge them.”

Mr Mohammed, 30, was an asylum-seeker in Britain when he went to Afghanistan in 2001. After his capture, attempting to board a flight to Britain with a false passport, the US accused him of conspiring to set off a “dirty bomb” in a US city.

These charges have since been dropped and, despite continued concerns from security officials, Mr Mohammed is one of three Guantanamo Bay inmates Britain has said it will accept when the camp is closed.

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