Free Yunus Rahmatullah, court urges
English judges have come to the aid of a 29-year-old Pakistani captured by British troops in Iraq and held by American forces in Afghanistan for more than seven years without trial.
The Court of Appeal said British ministers should end Yunus Rahmatullah's "unlawful detention".
The ruling came after British-based human rights lawyers employed a piece of ancient English common law in a bid to free Rahmatullah.
Legal charity Reprieve asked the Court of Appeal to grant "habeas corpus" relief.
Habeas corpus - Latin for "you may have the body" - is a procedure which requires a court to examine the legality of a detention.
Three judges directed the issue of a writ of habeas corpus, after a hearing in London, and said Rahmatullah should be freed.
Reprieve described the ruling as "historic" and "unique".
A spokeswoman said she expected British ministers to ask the American authorities to free Rahmatullah.
Lawyers representing Foreign Office and defence ministers and Rahmatullah are expected to discuss the next steps at a Court of Appeal hearing later this month.
Lawyers had earlier this year tried and failed to persuade the High Court to come to Rahmatullah's aid.