David Blunkett, the Home Secretary, will defy the Privy Council and civil rights campaigners this week over the 14 foreign terrorist suspects held in what has been nicknamed the "British Guantanamo Bay".
The suspects have been detained indefinitely without charge under powers granted to the Home Secretary in a law passed after the 11 September attacks.
The Home Office denies that their fate is comparable to that of the detainees held by the US in Camp Delta, because they can leave Britain - but only if another country will take them. They cannot go back to their homelands, where they could expect far harsher treatment than at the high-security jail at Belmarsh, where most are held.
They also have the right to appeal against the Home Secretary's decision to the Special Immigration Appeals Commission. However, 11 of the suspects have had their appeals rejected by the commission - a point Mr Blunkett will use when he faces the Commons on Wednesday as evidence that he is not detaining people unreasonably. Two other appeals are pending.
When the Anti-Terrorism, Crime and Security Act was passed, three months after the attacks in New York and Washington, it was agreed that it should be reviewed after two years by a statutory committee of privy councillors.
Last December, the committee, headed by a former leader of the Commons, Lord Newton of Braintree, said the detention of people indefinitely without charge should end "as a matter of urgency".
They suggested electronic tagging of suspects, and restricting their access to telephones and bank accounts. But Mr Blunkett will say the threat from al-Qa'ida and associated terrorist groups is too serious to allow suspected supporters to roam freely.
The Newton committee was a more powerful body than the normal parliamentary committee, in that its findings mean that the Anti-Terrorism Act could have ceased to be law if the Government had not arranged for it to be debated by both houses of Parliament.