Binyam Mohamed came to the UK as an asylum seeker in 1994
A British resident held in Guantanamo Bay has won the first stage of a legal fight to make the UK government release evidence for his defence.
The High Court has ordered a hearing to consider Binyam Mohamed's bid for a judicial review of the matter.
The 29-year-old, of west London, has been charged with war crimes in the US. His lawyers say the UK has proof his testimony was given after torture.
The Foreign Office said it was still working on the information requests.
Mr Mohamed is to face a military tribunal at the US detention camp in Guantanamo Bay, Cuba, and could face the death penalty if convicted of conspiring to commit terrorism.
He denies involvement in terrorism.
At London's High Court, Mr Justice Sanders ordered that an urgent hearing be held over Mr Mohamed's bid for a judicial review into the request for documents.
He said: "If it is correct that in the course of an interrogation, in which material supplied by the defendant [the UK government] was employed, the claimant [Mr Mohamed] was tortured, then it is arguable that there is an obligation to disclose material which may assist claimant in establishing before the American military court that he was tortured.
"Whether the court should exercise its discretion not to order disclosure can only be determined at a full hearing."
The US charge sheet alleges Mr Mohamed travelled to Afghanistan in May 2001 and trained at an al-Qaeda camp.
It says he then accepted instructions from al-Qaeda leader Khalid Sheikh Mohammed to conduct terror operations in the US.
The charges must be approved by the Pentagon official who oversees the tribunal system before Mr Mohamed faces court.
Mr Mohamed was detained in April 2002 as he tried to return to the UK from Pakistan.
He says he was taken from there to Afghanistan and Morocco for questioning before being transferred to Guantanamo Bay.
His lawyers say it has been established that Mr Mohamed was questioned by British intelligence officers for three hours in Pakistan, and want details released.
They are also seeking evidence he was subjected to "extraordinary rendition" - transport abroad for interrogation.
They want access to flight records from the UK-dependent territory of Diego Garcia, which they say could establish that planes used for "extraordinary rendition" refuelled there.
His lawyers also believe the government has proof that Mr Mohamed's genitals were repeatedly slashed with a razor blade while he was being held in Morocco.
They say their client travelled to Afghanistan and Pakistan in 2001 in a bid to resolve personal issues after developing a drug problem.
Foreign Secretary David Miliband formally wrote to his US counterpart Condoleezza Rice in August 2007, asking for Mr Mohamed's release.
A Foreign Office spokesman said: "We are in discussions with the US over Mr Mohamed's case and our request for his release from Guantanamo Bay and return to the UK still stands.
"We are providing Binyam Mohamed's legal representatives with some of the information requested… and continue to work on the outstanding elements of their requests.
"The charges that have been brought are primarily a matter for the US authorities, however we will continue our dialogue with them over the military commissions process including our outstanding concerns."
Mr Mohamed first came to Britain as an asylum seeker in 1994, aged 16. His asylum claim was never finally determined, but he was given leave to remain and went on to work as a cleaner in west London.
He is the last British resident held at Guantanamo Bay, following the release of four others in December last year.