It is now more than a year since four young British Muslim suicide bombers blew up themselves and 52 innocent people on the London transport system. The attack exploded official complacency about the threat posed by Islamist terrorism to the UK.
Britain has responded with new anti-terror legislation and more resources for the security services. According to one senior European policeman: "You can no longer accuse the British of being too soft or too reactive. The police are being driven by M15 to act early on intelligence and disrupt."
Yet efforts to improve relations with Muslim communities have faltered and there is little public debate on the issue. "For whatever reason, it's not core to our political debate and it probably should be," says Dominic Armstrong, a terrorism specialist with the UK-based Aegis Defence Services, a risk consultancy.
The US-led reaction to the attacks of September 11, 2001 severely weakened the hierarchy of al-Qaeda, he says, but was like "hitting a pool of mercury with a hammer". Islamist terrorism became more atomised and difficult to track.
Since last July, more than 40 individuals in the UK have been charged with terrorist-related offences. Hundreds have been arrested or detained, with police claiming they have disrupted as many as four terrorist plots. The number of terrorist suspects identified annually by M15 now surpasses 1,000 -- more than double that of two years ago.
Since police and intelligence services cannot follow every suspect -- full 24-hour surveillance of an individual may require 20 people -- they are left with tough decisions about which leads to pursue. "The word is 'prioritise"', says one experienced security official.
But this means some will inevitably escape the net: hence the repeated predictions by security officials that, some time in the next 18 months, another attack is likely to succeed.
The lack of a command-and-control hierarchy, such as that employed by the Provisional IRA, has made the terrorist cells more difficult to penetrate. This has also encouraged the security services to intervene earlier.
Peter Clarke, head of the Metropolitan Police's anti-terrorist branch, says that in the past, particularly during the IRA campaign, it was police policy to arrest suspected terrorists at or near the point of attack so as to secure sufficient evidence for a trial. Such a strategy now carries an unacceptable risk to public safety.
"We have to give ourselves the opportunity to intervene at earlier stages -- to attack the fundraising, to disrupt the logistics, to detect hostile reconnaissance -- because when we get to the point of attack the options are too limited," says Mr Clarke.
Yet an operation last month in Forest Gate, east London, in which police stormed a Muslim home and shot and injured an occupant, highlighted the danger of this approach: its capacity to inflame Muslim sentiment further. The raid involved hundreds of officers, some wearing chemical weapons suits. It uncovered nothing and appears to have been based on bad intelligence.
Indeed, government efforts to develop a coherent strategy for countering the radicalisation of Muslim youth have been stymied by lack of agreement about its causes.
Whitehall officials say concerns that the government was floundering in its efforts to win the trust of the Muslim community led Tony Blair to strip the Home Office of responsibility for race equality and cohesion and pass it this year to the Department for Communities and Local Government.
The move came amid mounting concerns that the Home Office, in charge of the police and M15, had mismanaged the Muslim Task Force, a group set up by the government with representatives of Muslim organisations to develop social and economic policies for tackling extremism and alienation. "The task force... failed to really gain credibility among sectors of the Muslim community that needed to become involved," admits an official closely involved with the initiative.
It was only a few days ago that three mainstream Muslim organisations announced they were hoping to implement one of the task force recommendations: the setting up of a body to help oversee mosques and imams. And yet, as the government's analysis of the July 7 bombings pointed out, evidence suggests that extremists are moving away from mosques to avoid detection. Instead, they organise in private homes or via the internet.
Indeed, the investigation into the July 7 bombings and other inquiries demonstrate the ease with which terrorist propaganda proliferates on the web. A report early this month from the Risk Advisory Group, a UK security consultancy, says the internet has "helped to define the new generation of home-grown, self-empowered extremists ... They can now discreetly plug into a community set far apart from the restraining norms and moral balance of their inherited social and familial networks."
Tarique Ghaffur, Britain's most senior Asian policeman, says certain elements within the Muslim community are in denial about July 7 and about the nature of al-Qaeda and its associates. But, expressing views shared by several colleagues, Mr Ghaffur says government strategy must go beyond questions of law and order to address issues of socio-economic deprivation and Muslims' lack of representation at senior levels of UK society.
According to Massoud Shadjareh, of the London-based Islamic Human Rights Commission, the fatal flaw in the anti-terrorist strategy is a refusal to acknowledge the extent to which foreign policy dictates the nature and pace of radicalisation.
The arrest last month of 17 terrorist suspects in Canada, a country that did not participate in the invasion of Iraq, suggests no government will be free of terrorism. But privately, many UK security officials agree that British participation in the US-led war and occupation has galvanised a new generation of extremists.
"The Muslim community has no control over the extremists in its midst. What motivates them is not reading the Koran but seeing atrocities being committed against Muslims around the world," says Mr Shadjareh.