Conservative MP Ann Widdecombe will defy her party leader and back the government's controversial counter terrorism legislation.

In Gordon Brown's toughest test since taking office, he faces a crucial showdown tonight when MPs vote on plans to extend the detention time for terror suspects from 28 to 42 days.

Ministers have spent weeks trying to cajole Labour backbenchers into backing the plans, but it's thought the Prime Minister will still have to rely on the support of some opposition MPs to get the legislation through.

Maidstone and the Weald MP Ann Widdecombe has told the Kent Messenger she will be one of them.

She said: "My view is that fighting terrorism is more important than fighting Gordon Brown.

"In an emergency, and terrorism is an emergency, it has always been the case that civil rights sometimes have to take second place to civil safety."

From the start Miss Widdecombe has made it clear she believes there must be a "sunset" clause so the legislation has to be renewed by MPs every year.

She said: "I believe that in any emergency the government has the right to ask Parliament for special powers; we did after all over Northern Ireland.

"But of course it's important those special powers are renewable."

Compensation could be offered to those released without charge, but Miss Widdecombe said it should not be a matter of course.

"I don't think it should be automatic.

"Every day police detain people and they are not always charged.

"It would depend on whether there were particular circumstances to the case" she said.