Ministers were accused today of creating a Guantanamo Bay on British soil where foreign terror suspects have been held without trial for almost two years.
The emergency internment laws introduced in the wake of the attacks on the United States on 11 September 2001 were also criticised as a "perversion of justice."
Amnesty International's damning report over the detention of terror suspects in Belmarsh and other high-security prisons comes two days after four Algerian men were finally cleared by the Scottish courts of offences under the Terrorism Act 2000.
The men spent four months in custody and a further eight months on bail with the charges hanging over them. Their lawyers said that their clients' lives had been ruined and are calling for a public inquiry to establish whether the prosecutions were politically motivated
Amnesty's report claims that the Government's anti-terrorism measures have created a "Guantanamo Bay in our own backyard". The human rights group said that emergency legislation introduced by the Home Secretary, David Blunkett, had created a "shadow" criminal justice system for foreigners.
By allowing them to be locked up indefinitely without charge or trial, ministers had failed to meet international standards, the group claimed.
The report, "UK: Justice Perverted under the Anti-terrorism, Crime and Security Act 2001", looked at the laws that have led to 14 people being detained at high security prisons as suspected terrorists. Six of the suspects will have been in detention for two years on 19 December.
Kate Allen, Amnesty International UK director, said: "The Act is discriminatory - there is one set of rules for British citizens and another for nationals of other countries.
"It allows non-nationals to be treated as if they have been charged with a criminal offence, convicted without a trial and sentenced to an open-ended term of imprisonment. In no respect can this be considered just. This legislation has created a Guantanamo Bay in our own backyard."
Amnesty also has misgiving about the workings of the Special Immigration Appeals Commission (SIAC), which was set up to allow the men to appeal against their detention. The human rights group, which has been monitoring SIAC, said neither the men nor their lawyers are allowed access to all the evidence. The SIAC tribunal, which has the equivalent status as the High Court, made "a number of disconcerting rulings". In particular, it denied detainees the presumption of innocence. The proceedings "did not guarantee even basic minimum fair trial safeguards".
Ms Allen said: "These individuals face indefinite detention on the basis of a lower standard of proof than would be necessary in a civil court case to recover damages following a car accident ... they can be held indefinitely on the basis of secret 'evidence'."
Amnesty said that SIAC appeared to have accepted evidence obtained through the torture of suspects detained by the US at Bagram air base in Afghanistan and at Guantanamo Bay in Cuba. "The use of evidence obtained under torture undermines the rule of law and makes a mockery of justice," said the document.Reuse content