In a massive crackdown on extremists following the London terror attacks, British authorities will deport in phases as many as 500 radical Muslims, out of which a dozen clerics will be sent to their homelands over the next two weeks.

The move follows Prime Minister Tony Blair's announcement last week of a purge on terrorists and extremists.

Immigration officials have already been given a list of names, compiled by MI5, and have been told to begin proceedings.

Among the first to be deported will be a dozen radical clerics. But hundreds of other foreign extremists, including some Islamic bookshop owners, writers, teachers and website operators will also go, the 'News of the World' newspaper reported.

"Just as the police operation over the past four weeks has been dynamic and fast-paced, so will our response," a senior home official was quoted as saying.

All 500 names have been taken from a 'watch list' of extremists compiled over the past 5 years by the Intelligence Service. Their identities are being kept secret so that they will not be able to go into hiding or mount a legal challenge.
   
The deportation process will begin after Home Secretary Charles Clarke returns from holiday this week.

Also read: The London Blasts

An initial wave of up to 100 people will be booted out in the next month, officials at both the Home Office and the Foreign Office revealed.

Another 100 foreign nationals will then be sent home by the end of the year. As many as 300 more will be sent home next year once the government has new laws in place to strip them of their British citizenship.

Over the next week, agreements will be completed with 10 African and middle eastern countries to make sure they will accept the extremists.