Thirteen suspected foreign terrorists imprisoned indefinitely without charge in high-security prisons won the right to take their cases to the House of Lords yesterday.
They were rounded up under legislation rushed through shortly after the 11 September terrorist attacks on America.
It allowed David Blunkett, the Home Secretary, to waive his obligations under the European Convention on Human Rights, which bans detention without trial under article 5. The Government insisted that the measures were essential to stop Britain becoming a safe haven for terrorists, but lawyers acting for the suspects argue that their human rights have been breached.
Three law lords said that the detainees could appeal to the highest court but gave no reason for their decision. The Government had hoped the issue would be closed last year when the Court of Appeal ruled that the detentions were legal.
Natalie Garcia, lawyer for two of the detainees, said: "It would have been scandalous if they didn't grant leave [to appeal] because it is a constitutional issue. It's a complete travesty of justice. There's no way people should be detained on this basis.''
The Home Office last night signalled its intention to defend the new laws vigorously in the House of Lords.
A Home Office spokeswoman said: "We maintain the view that while the public emergency continues to exist, these measures are necessary and proportionate. Our primary responsibility is to ensure public safety and national security.''
The Government says that it has to demonstrate only that it has "reasonable grounds to suspect" that detainees have links to terrorism.
It does not have to charge them with a crime or prove their guilt.
Most of the suspects have not been named but they include the radical cleric Abu Qatada.
He is wanted in Jordan for bombings in 1998 and British officials say he was an "inspiration" for 11 September.