Gordon Brown is likely to escape defeat in tonight's crunch Commons vote on extending the pre-charge detention of terrorist suspects to 42 days, the Tories conceded today.
Shadow home secretary David Davis said it looked as though the Government would win, even though 30 or more Labour rebels are expected to vote with the Opposition against the measure.
But he warned that the fight was not yet over and they would carry the battle to the House of Lords, where opposition is thought to be far more entrenched.
"I think it is unlikely that we will win," he told BBC Radio 4's Today programme.
"I suspect that the Government will survive the day but then it goes to the Lords and I think we will defeat it there."
Ministers have warned that the outcome of the vote is likely to be "very, very tight".
A revolt by around 35 Labour MPs would be enough to defeat the Government if all the opposition parties voted against it.
The result may hinge on the Democratic Unionists who are expected to meet this morning decide which way their nine MPs will vote.
Although talk of a deal has been hotly denied, many MPs suspect that ministers will come up with sufficient inducements to persuade them to back the 42-day extension.
In that case, it would need around 50 Labour MPs to vote against the measure for it to be defeated - a total the rebels acknowledge that they are unlikely to achieve.
Nevertheless the Government has been taking no chances.
Home Office Minister Tony McNulty disclosed that they were considering adopting an amendment to compensate suspects who were detained for longer than the current 28-day limit but were not subsequently charged.
He told BBC2's Newsnight last night that the idea seemed a "perfectly reasonable proposition".
"The Home Secretary (Jacqui Smith) will look at it and she will report back to the House," he said.Reuse content