Tony Blair, Charles Clarke, the Home Secretary, Sir Ian Blair, the Metropolitan Police Commissioner, and Ken Livingstone, the Mayor of London, have refused to lay the blame for the atrocities on intelligence failures.
The Government insists it does not want them distracted from the task of hunting the bombers. But the devastating impact of Thursday's blasts, which Mr Clarke confessed had come "out of the blue", has alarmed both ministers and police.
The Home Secretary has called for an urgent review of intelligence before the attack to ensure no crucial information was overlooked. The lessons to be learnt also came up in sessions of the Government's Cobra crisis management committee chaired both by the Prime Minister and Mr Clarke.
Anti-terrorist specialists believe they have had considerable success in thwarting planned bomb attacks by terrorists allied to, or sympathetic to, al-Qa'ida. They had relied heavily on electronic "chatter" between potential al-Qa'ida sympathisers, many of them foreign nationals, for tracking suspected terrorists.
MI5 will now go through a soul-searching as they face the possibility that the bombers were British nationals living outwardly respectable lives.
Mr Clarke said: "We are obviously looking very closely at all our intelligence to see if anything was missed. But, in fact, we don't think anything was missed. We have a very effective intelligence service, but we didn't predict this particular attack at this particular time. The reason for that is we are always looking for a small number of very evil needles in a very large haystack, which is the city of London."
Police and government made clear the decision to downgrade the level of the alert, from "severe-general" to "substantial", had been based on advice from the intelligence services. It had been taken by the Joint Terrorism Analysis Centre, which judged the risk had fallen slightly since the general election. Intelligence analysts had uncovered no evidence of a plot to coincide with the staging of the G8 Summit on British soil. Sir Ian added: "This is an imperfect world and an imperfect science."
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