Gordon Brown has insisted he did not do a 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 on Wednesday 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 on Thursday: "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."
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."
