A draft Bill outlined in the Queen's Speech in May set out plans to create offences to bring more terror suspects before the courts and is expected to lead to convictions for those accused of acts preparatory to terrorism.
Yesterday's attacks on London will also make it more difficult for the Conservatives and Liberal Democrats to oppose the introduction of identity cards.
But lawyers and civil rights groups urged the Government not to repeat the mistakes of the past. Peter Carter QC, chairman of the Bar's human rights committee, said he feared the Government would adopt emergency powers that would cause further resentment in Muslim communities but not make Britain a safer place to live.
Mr Carter said: "History has shown us that it is never good to rush through legislation. The laws passed to combat the IRA in the 1970s and 1980s proved a political and a legal disaster."
Mr Carter said the police and security services already had sufficient powers to deal with the threat posed by al-Qa'ida, including an offence of possessing items that were of potential use to a terrorist. Such items, he said, could include an A-Z of London.
Those arrested in the inevitable police raids that will follow yesterday's atrocities are expected to be detained under the toughest powers at the security forces' disposal.
Under the terms of the 2005 Prevention of Terrorism Act, the Home Secretary, Charles Clarke, has the option of using house arrest to detain terror suspects.
Mr Clarke told Parliament in February that he was considering introducing the offence of "being concerned in the commission preparation or instigation of acts of terrorism".
In a statement to the Commons, he said: "Some believe that the absence in this country of a terrorist outrage such as 9/11 or Madrid means that the terrorist threat has passed us by or failed to materialise. That view is short-sighted, complacent, ignorant of the facts and potentially cavalier in the disregard of the safety of this country."