Gordon Brown insisted today he had done "no deal" with Democratic Unionists to secure vital support for his 42-day terror detention without charge proposals.
The controversial measure was narrowly approved by the Commons by just nine votes last night thanks to the support of the DUP after 36 Labour MPs rebelled.
But the Prime Minister rejected claims that he had bought their backing, or that of some Labour MPs, with promises of action on issues such as extra cash for Northern Ireland.
He said at his Downing Street press conference: "There was no deal. There was no deal with the Democratic Unionist Party, no deal with the Ulster unionists generally.
"And I think for people to imply that is to take away from the strength of the argument about the need to tackle terrorism."
Mr Brown said: "Nobody knows more about the need to take action in preparation in case you have terrorist abuses than the people of Northern Ireland.
"And I believe that the people who voted for this voted on principle because they are persuaded by the argument."
He hit out at Conservative opposition to the extension from 28 days, accusing them of failing to engage in a national consensus on the need for tougher powers.
"I believe that they will regret their action in failing to support action that is necessary in our country to deal with both the causes and the problems associated with terrorism.
"I would still appeal to them and to other parties to join the consensus that we need to take action, to be prepared," he added, after opponents vowed to block the legislation in the House of Lords.
In a direct warning, he told them: "I do not want to have to come to the House of Commons and tell them that a terrorist incident had occurred but we have not been properly prepared because we failed to take the legislative measures necessary."
Join our new commenting forum
Join thought-provoking conversations, follow other Independent readers and see their replies