The realisation that Britons are ready to bomb their fellow citizens is a challenge to the whole of society, writes Jonathan Freedland
Like an earthquake, the London bombings have brought an aftershock. The police announcement that last Thursday's explosions on the underground and on the Number 30 bus were, apparently, the work of British suicide bombers is the most shocking news to come since the attacks themselves. It is also the bleakest possible development.
Now we know that what happened on July 7th was not just the worst terrorist attack in British history, it was also a first: the first suicide bombing on British soil. That is especially depressing for a reason Israelis, Iraqis, Indians and Russians will understand well. For the suicide bomber represents a unique kind of threat; an enemy that does not fear being captured or killed is always bound to be more potent. To give one practical example, warnings about suspect packages on the tube are futile against a man ready to detonate a bomb in his lap.
More deeply, these men will have hoped their deaths will endure. One detail was striking in Tuesday's police briefing: it was that property identifying the men was found in each location, including items belonging to one man found at both Aldgate and Edgware Road stations. That cannot have been an accident. It suggests these killers wanted their names to be known; they were proud of what they did.
It is hardly a surprise. For the suicide bomber aims to be a martyr, his face burned on to a thousand webpages, his action a model to be emulated. Who knows, perhaps a video - like those released by the men of Hamas and Islamic Jihad - is waiting to be found in one of those Leeds homes. The danger here is the process which represents al-Qaeda's modus operandi, with one outrage inspiring others.
That these men wanted to kill and die is bad enough. That they were, it seems, born and raised in Britain is even worse. If they had been a foreign cell, like that responsible for the Madrid bombing, we could have comforted ourselves that this was an external phenomenon, an alien intrusion. The remedies would have been obvious: tighter border controls, more international co-operation.
But there can be no such comfort if these killers were British citizens. We could shut out every last asylum seeker, expel every illegal immigrant, and it would make us no safer. This attack came from within.
British Asians will find that especially dispiriting. They know from harsh, direct experience what it will entail: suspicious looks and worse every time they get on a train or bus. The Metropolitan Police rightly called yesterday for no smearing or stigmatising of entire communities. But the danger of ostracism is great.
British Muslims rightly insist that there can be no collective guilt - not for bombs whose victims included several Muslims - and their leaders have been vocal in their condemnation of the killings. The Muslim Council of Britain is considering a public demonstration against terror.
And yet the news about the origins of the bombers will increase the intensity of a process that was already under way - the soul-searching of a community which now knows it includes suicide bombers among its young. As one young Muslim said last weekend: "It isn't good enough for Muslims to merely condemn terrorism . . . We need to clamp down hard on the shoddy theology that people like al-Qaeda use to justify what they do." That kind of voice will surely be emboldened now.
Fiyaz Mughal, who runs the interfaith Diverse Trust, told me an agenda is already forming for British Muslims. First item would be a stepping up of efforts to train British-born imams - rather than relying on foreign leaders with an incendiary line in rhetoric. Next, moderates will demand that British Muslims report those they suspect of spreading jihadist fury. Mughal admits that literature glorifying 9/11 and the like is easily available in the British Muslim community; now, he predicts, those handing it out could find themselves turned in. Finally, he hopes for new Muslim engagement in the political process. Their demands will be clear, calling for a change in the foreign policy areas - Iraq, Afghanistan, Israel-Palestine - that they believe have ignited the extremists in their midst.
Of course, this burden cannot fall on Muslims alone. The realisation that Britons are ready to bomb their fellow citizens is a challenge to the whole of our society. One security source I spoke to before the police revealed their findings, presciently guessed that the culprits were "a UK group, homegrown, having bypassed al-Qaeda training camps". He reckoned they would have drawn on the pool of young Muslims so disconnected and disenfranchised that they are easy prey to the extremist sermons heard in some mosques, to the wild, conspiracy-theory packed tapes sold outside and to the most fire-breathing websites. The proliferation of that material represents a deep challenge to British Islam; that disconnection and disenfranchisement is a challenge to Britain itself.
How will this revelation affect London? Some may be reassured by the knowledge that the bombers are dead, rather than at large. Others will hope that, if there are more jihadist cells in Britain, the police will now have the leads to find them.
But the truth is, it is still too early to tell what exactly it is we are dealing with. Is this a one-off, as 9/11 and Madrid turned out to be? Or is this the beginning of a campaign of suicide bombing, like the one waged on Israel for nearly 10 years? My hunch is that the much-discussed stoicism and resilience so far displayed by Londoners is the fruit of the first assumption: that this is a horrible event, never to be repeated.
That might explain the calmness which has so surprised Israelis and Spaniards. The Spanish newspapers have been stunned by the British failure to take to the streets, to stage a mass demonstration like theirs last March. Israeli reporters in London last week marvelled at the absence of a crowd of passers-by, bellowing into a microphone, demanding revenge - the scene that so often follows a suicide bombing in Israel, like the one that hit a shopping mall in Netanya yesterday.
We Britons can congratulate ourselves on our phlegmatic cool so far. But we should start to wonder what would happen to us if these attacks became a fact of life, as they have long been in Israel (and are now in Baghdad). Would we find restraint as easy a policy to follow if there was a bomb on the tube or the bus every other day? I hope never to know the answer to that question. I want it to stay hypothetical for ever. But a menace we have until now seen only from a distance has stepped right up to face us. The ground is still trembling beneath our feet.