Readiness: As Ken Knight, commissioner of London Fire Brigade, spoke yesterday about the 200 fire-fighters who took part in yesterday's rescue efforts, he remarked that the attacks were not unexpected.
"These are the kind of events that London firefighters have been preparing and training for," he said.
London's deputy police commissioner, Brian Paddick, said that, after the terrorist attacks in the United States in 2001 and in Madrid in 2003, the police were prepared for bombs in London.
"We are clearly shocked but we are not surprised by what has happened," he said.
Mr Paddick acknowledged, however, that neither the police nor Britain's security service, known as MI5, had knowledge of a specific threat to London.
He added that, in recent months, the security alert level had been "lowered slightly" from "severe general" to "substantial".
Thousands of police officers left London for Scotland this week to join the 11,000-strong force protecting G8 leaders meeting at Gleneagles.
Politicians and security experts agreed that yesterday's attacks on London were almost certainly planned to coincide with the G8 meeting.
As critics suggested that the attacks were the result of an intelligence failure by police and MI5, police sources said recent intelligence efforts had foiled terrorist plans on almost a weekly basis.
London's former police commissioner, John Stevens, warned earlier this year that up to 200 violent Islamists were active in Britain, making a terrorist attack on the capital almost inevitable.
Britain's spending on security has risen from £950 million (€1,387 million) a year before September 11th, 2001, to £1.5 billion this year. It will reach £2.1 billion in 2007.
MI5 plans to double its staff to 3,000 by 2008 in a recruitment drive that is targeting Arabic speakers and members of Britain's ethnic minorities.
Yesterday's attacks bore a striking similarity to the 2003 Madrid bombings of four commuter trains during the morning rush hour. British security personnel have worked closely with their Spanish counterparts during the past two years, sharing intelligence and studying prevention methods and emergency response techniques.
Mustafa Setmarian Nasar, who is widely believed to have planned the Madrid attacks and who remains at large, lived in London during the 1990s, and some security experts fear that he may be in contact with British associates.
The speed and efficiency of the emergency services' response to yesterday's attacks owes much to the experience gained by British authorities during the IRA's 30-year bombing campaign.
Doctors said that the timing of yesterday's attacks, around 9am, was fortuitous because staff were already at work in London's major hospitals.
IRA bomb attacks and accidents such as the fire at King's Cross station in 1987 have given London's hospital services valuable experience in treating trauma injuries.
For the first few minutes after each attack yesterday, London Transport staff were responsible for calming passengers and organising their evacuation.
The skill shown by such staff owed more to their personal qualities than to training they were given, according to a London Underground manager, who asked not to be identified.
"After 9/11, we were given one instruction about how to deal with a nerve-gas or chemical attack.
"They told us that if you see one person falling, do nothing because it could happen for any reason. If you see two falling, run - because there's nothing you can do. That's all the training we ever got," he said.