Mr Mohamed, a British resident, claims he was tortured in US custody
The High Court has taken the unusual step of reopening a controversial judgement in the case of former Guantanamo detainee Binyam Mohamed.
It had agreed to a government request not to publish details of admissions by US officials over the way the UK resident was detained and treated.
Judges said the US might "re-evaluate its intelligence-sharing relationship", which could affect national security.
The government said the US remained opposed to any further disclosures.
They reopening of the case stemmed from submissions by Mr Mohamed's lawyers and the media.
The two judges, Lord Justice Thomas and Mr Justice Lloyd Jones, say they will set out their reasons for reopening their judgement "in due course".
But lawyers for Foreign Secretary David Miliband will still be able to argue that the information should not be made public.
US position 'opaque'
Ethiopian-born Mr Mohamed, 30, claims he was subjected to torture and cruel, inhuman or degrading treatment with the consent of UK authorities after being detained in Pakistan in 2002. The US denies the claims.
During a High Court hearing in 2008, lawyers for the foreign secretary said the US government remained opposed to publication of certain paragraphs outlining Mr Mohamed's treatment, even under President Barack Obama's new administration.
Mr Mohamed's lawyer, Dinah Rose QC, told the two judges it had since become clear from statements made by Mr Miliband and others that this was not correct and the true position of the new US administration in fact remained "opaque".
The appeal to reopen the judgement was launched by a number of media organisations including the BBC, Guardian News and Media, Times Newspapers and the New York Times.
Clive Stafford Smith, director of human rights organisation Reprieve, said: "It is long past time that this evidence was made public.
"How can it be that two governments that purport to uphold the rule of law be working together to cover up crimes committed against Binyam Mohamed?"
Responding to the High Court decision to reopen the judgement, the Foreign Office said the foreign secretary had raised this case with US Secretary of State Hillary Clinton.
"Secretary Clinton made it clear that the position of the US administration on the disclosure of US intelligence material had not changed," said the FO.
"In the light of President Obama's recent decision to release highly classified Department of Justice papers, we have checked again with the US whether this indicates a change in the US position on the release of a summary of US intelligence by the UK Courts.
"The US made their position clear that disclosure 'could likely result in serious damage to UK and US national security'."
Shadow foreign secretary William Hague argued that the foreign secretary needed to "bring this saga to an end".
"As we have said all along, he should take the simple step of asking the new Obama administration for the right to release the controversial paragraphs," he said.
"The foreign secretary's refusal to take this simple step is baffling and does nothing to dispel allegations of Britain's complicity in torture or the government's attempt to cover it up."
Liberal Democrat foreign affairs spokesman Edward Davey said President Obama's openness about America's use of torture during the Bush administration had exposed the government's position.
"This return to court is humiliating for David Miliband. If the judges were to rule for full disclosure, it would leave serious question marks over his position as well as being a great day for British justice," he added.
Mr Mohamed was the last British resident to leave Guantanamo Bay, returning to the UK in February.