There is pressure on the Home Secretary to order the raids to begin but the prison population is at a record level, and officials do not want the suspects held together.

Arrests had been expected by now after the Home Secretary said that he would move swiftly against those who foment, justify or glorify terrorist violence. Last night the Home Office would not comment on the reasons for delay.

Ministers have said that while Tony Blair declared “the rules have changed” on how Britain deals with extremists, they face a long and costly legal battle to remove any of those named on the list of suspects.

Lawyers are believed to have questioned deportation orders planned against prominent dissidents expected to be among the first group to be seized.

The Prime Minister, who returns to Downing Street today, has made clear that he wants to see swift action against extremists in Britain. But he may face problems from the EU, which is planning a directive that will effectively ban member states from deporting foreigners to states where they may face persecution or torture. Plans to be unveiled tomorrow will also lay down how long people can be detained pending deportation.

A costly surveillance operation is under way to shadow the first groups to be seized in case they try to go into hiding.

Whitehall officials are concerned that the courts could be jammed by appeals as many who fear that they are suspects have already briefed lawyers to intervene immediately if they are arrested.

Suspects whom the Government had hoped to deport swiftly, on suspicions that their identity documents used to enter Britain were fake, have the right of statutory appeal.

The only militant the Government has moved against since the London bombings has been the founder of the al- Muhajiroun group, Omar Bakri Mohammad. Mr Clarke took advantange of the Syrian-born preacher going to Lebanon on holiday to ban his return.

Jordanian officials are due in Britain to arrange the hand-over of the militant Islamic cleric Abu Qatada, one of the first suspects arrested this month. Awni Yarfas, Jordan’s Interior Minister, said that talks will be held on how quickly they can take custody of the man described as “al-Qeada’s spiritual ambassador in Europe”.

Nine of ten men picked up in raids this month are to be sent back to Algeria.

The Federation of Muslim Organisations in Leicestershire has decribed the Government’s response as “knee-jerk”.

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