Britain has announced a list of what it calls "unacceptable behaviors" in support of terrorism that could lead to the deportation or banishment of foreign-born Muslim clerics.

The list published by the Home Office applies to anyone who is not British and who foments, justifies or glorifies terrorist violence through the written or spoken word.

Home Secretary Charles Clarke says he needs the power to expel or bar radical Islamic preachers in the aftermath of the July 7 terrorist attacks that killed 52 London commuters and four suicide bombers.

"I have an obligation in particular to stop people coming into this country who could get young people in particular to behave in the kind of appalling way we saw in July," he said. "We want to ensure that those who foment, justify, glorify terrorism are not able to be in this country."

Mr. Clarke says the special powers are not intended to stifle free speech or legitimate debate about religion or other issues. But he says they are required because the terrorist threat remains real and significant.