London was back on a high state of alert last night as Scotland Yard warned of the possibility of a terrorist attack over the Christmas and New Year period.
While stressing there was no intelligence of a specific threat, Assistant Commissioner David Veness said Christmas was "a particularly vulnerable time" for the capital, which remained liable to attack by Islamic extremists or Irish republican dissidents.
The police launched an advertising campaign to raise public vigilance as the Home Secretary, Mr David Blunkett, resumed battle in the Commons to overturn a series of Lords' amendments to his controversial Anti-Terrorism, Crime and Security Bill.
At the same time a team of three detectives flew to India to interview a Muslim pilot suspected of plotting suicide hijack attacks on the Houses of Parliament and London's Tower Bridge.
Mr Veness said: "We have to take everything, wherever it might be in the world, seriously.
"The consequences of not doing so could be horrendous."
He was speaking against the backdrop of London talks between Mr Blunkett and the US Attorney General, Mr John Ashcroft, who refused to rule out the possibility that Osama bin Laden could be executed if captured and sent to the US for trial.
Mr Ashcroft was answering questions about the weekend suggestion by the Defence Secretary, Mr Geoff Hoon, that if British troops captured bin Laden he would only be handed over to the Americans, provided assurances were given he would not seek the death penalty.
However, despite ongoing media interest in the possibility, Downing Street has made it clear it is theoretical and that, should British personnel in the field find Osama bin Laden, he would automatically be placed in American custody.
Speaking at the American Embassy, Mr Ashcroft described terrorism as "a threat against the civil by the savage".
He repeated President Bush's warning that the war on terrorism was broader than the eradication of the individuals responsible for the September 11th attacks.
As he did so the Conservatives were expressing "grave misgivings" over continuing speculation about the deployment of British troops as part of a stabilisation force for Afghanistan.
The Shadow Foreign Secretary, Mr Michael Ancram, repeated his concerns about "nation building" and pressed for assurances "that any involvement will be time limited, will not lead to mission creep, and will not see our armed forces being sucked into a long-term policing role from which it would be difficult to extricate our selves in the future."
Downing Street repeated that no decision about troop deployments for an international force had yet been taken.