"Both the method of attack and the timing of this incident were completely predictable," says Charles Shoebridge, a former counterterrorism intelligence officer. "This incident shows that irrespective of previous successes in thwarting attacks, there was a major failure to predict and prevent the attack.
"If you do not have intelligence beforehand of an attack, this kind of incident is difficult to prevent - in mass transportation systems it is impractical to have searches and screening," he adds.
Yet few people were expecting a backlash against the authorities. Anger against the Iraq war bubbles below the surface here, and a certain frustration has emerged in protests at the G-8 in Scotland.
But Sam Hardy, an analyst at Royal Institute of International Affairs, says: "The British people won't lay any blame at the door of Tony Blair."
"There will be some who link this to the war in Iraq, but the initial response will be more in terms of solidarity - with the government and with your neighbor - rather than laying blame," Mr. Hardy adds.
London is home to large Islamic communities. Some British Islamic groups condemned the attacks. Sir Iqbal Sacranie of the Muslim Council of Britain said: "These terrorists, these evil people want to demoralize us as a nation and divide us. All of us must unite in helping the police to hunt these murderers down."
But other Muslims here took a hard line on the attack. "Muslims around the world are being oppressed by the West. Do you expect Muslims just to lie down and die or do you expect them to fight?" says one watchmaker. "I do not think that this will help the Muslims in Britain - it will only make things difficult. After 9/11 and the bombings in Madrid, life became more difficult for us," he says.