The debate over the Anti-Terror Bill looks likely to be one of the biggest challenges to Gordon Brown since he became PM.
Countless legal experts have stepped up to criticise the increase in pre-charge detention from 28 days to 42.
Those expected to vote against the bill, published tomorrow, come from all political persuasions. Surprisingly, they even include some who previously backed Tony Blair’s failed attempt to introduce a far longer period of 90 days.
Fabian Hamilton, a Labour MP, is one of these. He has since listened to the arguments of numerous liberal voices and now believes the changes are “bizarre” and “random”.
His conversion is partly down to a visit to one of George W. Bush’s so-called “Axis of Evil” states.
“I have been to Iran since then, and to China, and it has persuaded me of the importance of preserving our liberties,” he says. “Iran is civilised with splendid people but a dreadful judicial system." Dissent within the Labour ranks is widespread, he says. "I have spoken to a lot of colleagues and many are deeply unhappy.”
One theory is that Brown is not as committed to 42 days as it appears and that the bill is a cunning plan to make the Tories look soft on terror.
David Davis, shadow home secretary, has made a strong liberal case for retaining the status quo – but in a newspaper last Sunday he acknowledged the issue had previously caused splits within his party. “This may cost us some votes.,” he said.