Maidstone MP Ann Widdecombe is set to support Gordon Brown in his bid to lock up terror suspects for up to 42 days.

She may break Tory ranks in backing the counter-terrorism bill set for a knife-edge vote in the Commons next week.

But she will only do so if there is a clause which allows the legislation to be reviewed annually.

She told the BBC: "My reasoning is very simple indeed. It's that if we have a state of emergency then the government should be able to ask parliament for emergency powers, as we did for example over Northern Ireland … providing that the legislation does not remain on the statute books indefinitely until somebody gets around to repealing it."

The government's proposal has attracted strong opposition from civil liberty groups and is expected to prompt a large Labour rebellion.