Britain could suffer a Madrid-style atrocity in the general election campaign, Charles Clarke warned as he battled to win support for anti-terrorism legislation including house arrest without trial.
Insisting the new laws had to be in place within weeks, the Home Secretary refused to back down on the principle of "control orders" yesterday, although he hinted that judges could be given stronger powers to review them.
The measures are being opposed by the Tories, Liberal Democrats, many Labour MPs, civil rights groups and much of the legal profession.
In heated exchanges at Prime Minister's Question Time, the Tory leader Michael Howard said the Government was steamrolling through the plans without proper debate and was "using national security for political point-scoring". But Tony Blair warned that Britain faced "terrorism without limit" and claimed al-Qa'ida would murder thousands of Britons if it got the chance.
The Home Secretary gave a similar ominous warning as he opened the second reading debate of the Prevention of Terrorism Bill, which gives him sweeping powers to restrict the movement and behaviour of terrorist suspects.
In the event, the Government's majority was halved to 76 votes last night when MPs voted 309 to 233 to give the Bill a second reading. A total of 32 Labour MPs, including the former cabinet ministers Clare Short and Frank Dobson, voted against the Government.
Other Labour MPs who voted against included the former sports minister Kate Hoey, the former defence minister Peter Kilfoyle, the former transport minister Glenda Jackson, Bob Marshall-Andrews QC and Alan Simpson. Many more Labour MPs abstained, including Robin Cook, the former foreign secretary. He is leading a backbench move to amend the Bill before it goes to the Lords.
Tory MPs and Liberal Democrats also voted against. There are almost certain to be changes to the Bill before it goes to the Lords next week.
Mr Clarke is the first minister to express fears that al-Qa'ida could be plotting an outrage before the general election expected on 5 May. He said: "Terrorists are moving very rapidly in these areas and it may be necessary to move very rapidly to deal with them. I cite only the most recent example in Europe. The Madrid atrocity took place in the Spanish general election campaign.
"Maybe such things can always be possibilities here too. In those circumstances, it's necessary to be able to take what steps are necessary to stop that happening."
Control orders, which could include bans on telephone or internet use, would be used "sparingly and only in very serious cases", Mr Clarke told MPs.
The Labour left-winger Brian Sedgemore rounded on his colleagues. "Our debate is a grim reminder of how the Prime Minister and the Home Secretary are betraying some of Labour's most cherished beliefs," he said. "It is truly terrifying to think what these MPs will vote for next. I myself can only describe this as New Labour's descent into Hell and Hell is not a place I want to be."
David Davis, the shadow Home Secretary, said: "The easy, but in my view irresponsible, route would have been to roll over and let the Government legislate in ways that reduce liberty, harm long-standing important traditions of British justice, and which may even worsen rather than improve the terrorist situation."