Amid chaotic scenes in the Commons, the government has offered a major concession on its anti-terror plans.

The home secretary said on Monday he would amend his Prevention of Terrorism Bill in the House of Lords, to allow the High Court, rather than his office, to issue controversial control orders.

However Charles Clarke added that new powers would be given to the police to detain terror suspects before a judge could pass an order allowing for house arrest or other restrictions on movement or communications to be put in place.

And the court would only be allowed to decide if the law was being correctly applied, as opposed to making a judgement on the level of threat, which would remain the government's responsibility.

But MPs complained that the move had come unnecessarily late and made a "farce" of the Commons debate.

Letter

At the start of the debate it emerged that Clarke had written to his Conservative shadow David Davis outlining his new position.

"I propose to amend the Bill so as to provide for 'derogating' control orders to be made by a judge in the High Court rather than as now by the secretary of state," the letter said.

"I shall make this clear during the debates today. The new procedure for derogating control orders will be as follows.

"The secretary of state would make an ex-parte application to the High Court for an order. he application would be heard by the judge as quickly as possible - say within 24-48 hours.

"The judge would look at all the material on which the application was based and decide whether there was a prima facie case - if so, he would make the order.

"To cover the emergency situation where we need to stop the subject of the application from disappearing in the period between the secretary of state making the
application and the order being served, I propose to give the police a new and specific power of arrest and detention so that he or she could be detained pending the judge's decision on whether to make the order following the application and the order, if agreed, being served."

He added that this would "fulfil the national security concerns, which are my primary concern".

Debate

But with MPs unable to see the new proposal in legislative form, the Commons was left confused over the detail and resigned to voting on the original bill.

The Commons will have to wait until the Bill comes back from the Lords next week before making its final decision, putting off an expected Labour rebellion.

Tory spokesman Dominic Grieve said: "We are being asked to pass this legislation which is of huge constitutional and legal significance - and we are being asked to do it on the basis of promises which will be fulfilled elsewhere.

"I have to say to the House that that is an impossibility."

And former Conservative home secretary Kenneth Clarke added that he had never heard of such a procedure being followed before, saying: "It is a complete outrage... it reduces our proceedings to a farce."

The home secretary argued that it was right to give MPs as much detail as possible on his latest thinking.

"I felt that I had come to a set of preliminary conclusions. I thought it would help matters if I then set out where we were," Clarke said.

"I have come to the view that there is merit in achieving as wide a consensus as possible," he added.

Poll

Clarke will have been buoyed by an earlier YouGov poll for the Telegraph, showing that 61 per cent of the public believe that national security and the prevention of terrorism matter more to them than the civil liberties of terror suspects.

Three quarters of respondents agreed that it may sometimes be necessary to take action against people who have not yet committed an offence but about whom the intelligence services have evidence that they are planning an act of terrorism.

But while many are prepared to accept the word of a minister, 33 per cent would feel happier if the decision to impose a control order were taken by a judge rather than the home secretary on his own.