“Accordingly,” Rauf continues, “all of us — Muslim and non-Muslim — must work together and give the police all the necessary co-operation and assistance that is within our means, in order to help track down those who planned and perpetrated these bombings. While they remain at large they are a dangerous threat to us all.”

He reads from a letter circulated by the Muslim Council of Britain to “imams, ulama, chairs and secretaries of mosques, Islamic organisations and institutions”. A sea of brown eyes and brown faces gaze at him obediently, some anxious, some puzzled, some drowsy in the heat and languor of the afternoon. One small boy in the front row rocks back and forth muttering verses from his copy of the Koran. Trains rattle by the shabby building and, beyond, all London lies hot, clogged and anxious amid the bomb scares and the sunshine that cares nothing for human grief.

“Peace, insh’Allah,” concludes Rauf — peace, God willing.

Rauf and the school secretary, Shamsul Hoque, both of them genial, smiling, eager, gather a group of 15 and 16- year-olds around me. Beyond a low rhythmic murmur rises from another group, seated in a square, learning Koranic verses. “Go on, tell him how you feel, what you think,” Rauf tells my boys.

But they are shy. A few admit they have had nasty looks in the street or people moving away from them on buses since 7/7. I ask why they think the bombers did it.

Ahmed speaks quietly of insults to Islam in Kashmir, Palestine and Iraq. With a pained expression, Ruhul asks why the media said it was Islamic terrorists as soon as the bombs went off.

Hussain is even upset by our pronunciation. “You all say MuZlim and it sounds like an insult. It should be MuSSlim." I ask them what they would do about injustice and insult. “Protest,” they all say, “but not bomb.” They had their own local anti-Iraq war demonstration of which they seem proud; but they are also proud of the fact that, being British, they are free to have such demos. They have been taught — and firmly believe — that suicides go straight to hell, that “He from whose hand and tongue his neighbour is not safe is not a Muslim.”

Gentle, sweet-natured, these earnest British-born children, who have to explain the terrible news to their Bangladeshi-born parents, seem to be all that we would want the Muslim British to be — clear about and proud of both their identities, happily holding two worlds in their young heads.

And yet, we now know, other British Muslim boys decided one of these worlds was absolutely right and the other so absolutely wrong that its inhabitants deserved to suffer and die.

What happened? Is the answer to be found in the flicker of hurt in the brown eyes of Ahmed, Ruhul and Hussain? Or are there schools ruled not by genial Rauf and Hoque but by warped teachers who teach their children only to die?

Two long, slow inward spirals have marked the aftermath of the London bombings. The first is the investigation that, finally, zoomed in on that chilling, blurred CCTV picture of a killer setting off on his task with his rucksack. The second is the spiral of national introspection that has now settled its inward gaze on the psyche of British Muslim youth and on the increasingly fraught and ambiguous word “multiculturalism”.

Academics have observed a change within British Muslim society that became apparent in the 1980s. Whereas a previous generation had pursued ideals of integration, young Muslims suddenly wanted to assert their distinctive character by identifying with the global umma of Islam. It was a community that seemed to provide a superior identity to any on offer in Britain.

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