------- first dual citizenship, then what ? jch -------
Tighter rules over citizenship
British citizenship can be revoked from immigrants who "seriously prejudice" the UK's interests, under new laws coming into force on Tuesday.
There is widespread speculation that the measures will be used against controversial Muslim cleric Sheikh Abu Hamza.
He was banned from preaching at Finsbury Park mosque in north London this year because of "inflammatory" remarks.
The new powers come under section four of the Asylum, Immigration and Nationality Act 2002.
Applying only to those with dual nationality, they could lead to undesirables being deported from the UK.
Home Secretary David Blunkett said British citizenship was a "privilege" which should not be acquired by deception or abused by people "acting against the UK's vital interests".
He would thus "prepare a case" under the new laws to take action against anyone who had acted in a way which was deemed incompatible with holding British citizenship.
Home Office minister Beverley Hughes said last month that Mr Hamza and others were "being very, very closely monitored".
Other measures
Andrew Dismore, Labour MP for Hendon, called for the radical cleric to be deported under the new powers.
"I think Abu Hamza should be a prime candidate under these new powers, if not at the very top of the list," he said.
"He has done nothing but run down Britain ever since he got his nationality.
Abu Hamza should be a prime candidate under these new powers, if not at the very top of the list Labour MP Andrew Dismore "Why does he want to stay here if Britain is such a horrible place to live?
"He wants to turn Britain into a Taleban-style state and has no place in this country.
"He fulfils the criteria of this legislation for his nationality to be removed and then for him to be removed."
The Egyptian-born Mr Hamza came to Britain in 1980 and was granted British citizenship after marrying an English national.
If the authorities decided to take action against him under the new powers he would have a right to appeal against being removed from Britain.
Other measures coming into effect on Tuesday are designed to stop failed asylum seekers delaying their removal from Britain by "abusing" the appeal system.
They also crack down on illegal working by giving immigration officers new powers to enter and search business premises.