Secret evidence cannot be used in trials of civil damages claims, the highest court in the land ruled today in a judgment hailed as a "victory for open justice".
In a majority ruling the Supreme Court dismissed a Government appeal in a case which arose in relation to High Court compensation actions brought by former Guantanamo Bay detainees.
Nine justices had been asked to decide whether courts have the power to order a "closed material procedure" for the whole or part of a trial of a civil claim for damages.
The case at the centre of the appeal related to compensation claims brought by a number of former detainees over their alleged detention, rendition and mistreatment by foreign authorities - claiming that the Government had been complicit in what they say happened to them.
The Government and security services had wanted to use secret information in their defence at the trials of the actions.
But in May 2010 Court of Appeal judges declared that it was not open to the courts to order a closed material procedure in an ordinary civil claim.
The claims by the detainees settled before the Supreme Court hearing, but the appeal went ahead to clarify the law on what was described as a "point of general importance".
And today the Supreme Court upheld the decision of the Court of Appeal by a majority.
Corinna Ferguson, legal officer for Liberty, which intervened in the case, said after the ruling: "The Government should be humbled by this strong defence of the principles of fair and open justice.
"The law already provides ample protection from disclosure where there are genuine national security concerns, and the court has made it clear that there are no compelling reasons for change.
"We hope ministers will now abandon proposals to introduce yet more secrecy into British courts."Reuse content