Miliband now has a week to decide whether to comply with the order to release of the documents pertaining to Binyam Mohamed's detention. The British government has argued the release of the documents could compromise national security, and it could appeal the court order.

The High Court made the ruling in the case of Mohamed, who was captured in Pakistan in April 2002 and accused of conspiring with al-Qaida leaders to attack civilians. His lawyers say the British government is withholding information about his treatment in U.S. custody which is critical to his hope of receiving a fair trial.

"The information held by the foreign secretary is not merely necessary, but essential, if Binyam Mohamed is to have his case fairly considered," Judge John Thomas wrote in the 75-page judgment.

Mohamed claims he was transferred illegally from Pakistan to Morocco after his arrest and alleges he was tortured during his 18 months in detention. Neither the United States nor Britain has disclosed any information about his time in custody until he arrived at Guantanamo Bay in 2004.