Home Secretary Jacqui Smith has said that plans to extend terror detention to 42 days will be dropped from the Counter-Terrorism Bill.
It follows a heavy defeat for the government in the House of Lords, which threw out the plan by 309 votes to 118.
Ms Smith said instead the measure would be in a separate piece of legislation to be brought to Parliament if needed.The Tories said the new legislation was "bizarre", the Lib Dems said Ms Smith was in "humiliating retreat".
In an emergency Commons statement, Home Secretary Jacqui Smith said the measure would instead be the subject of a separate piece of legislation to be brought before Parliament if required.
Flanked by the Prime Minister, she said: "Some may take the security of Britain lightly - I don't."
To Tory jeers, Ms Smith said she was not prepared to leave Britain "unprotected" against the terrorist threat.
The Counter-Terrorism Temporary Provisions Bill stood ready to be introduced
"if and when the need arises".
Peers voted 309 to 118 to reject a controversial proposal to hold terror suspects for up to 42 days without charge.
Ms Smith accused critics of "being prepared to ignore the terrorist threat for fear of taking a tough but necessary decision" and said she still believed the stronger powers could be needed.
The latest bid to extend pre-charge detention for terror suspects was rejected by a coalition of Tory and Liberal Democrat peers and Labour rebels.
They backed a move by crossbencher Lord Dear, a former chief inspector of constabulary, to bar any extension beyond 28 days in the Counter-Terrorism Bill.
Shadow Security Minister, Pauline Neville-Jones, said:"The vote was decisive.
"The proposal to extend pre-charge detention failed on three significant grounds: necessity, desirability and practicability.
"On all sides of the House of Lords the majority view - drawing on significant experience in policing, security and the law - was that these provisions should be completely removed."
This is a sensitive issue in light of the fact that there is a trial being heard currently in which the defendants stand accused of attempting an attack on Glasgow Airport. One of the men on trial is University Hospital of North Staffs doctor Mohammed Asha.
Do you think this bill should have been defeated? Ultimately wasn't this to protect our country from the threat of terrorism? Should the Home Secretary resign after this embarrassing defeat?