But it's not just gang culture. A while ago I wrote a piece for this magazine about my attempts to confront this kind of anti-social behaviour on the train journeys I regularly took from Woolwich to central London. What came out of it was the complete moral inversion that had taken place. If asked politely to turn music down, take feet off seats, or not swear so loudly on mobile phones in front of children, people appeared genuinely shocked at what they obviously saw as outrageous rudeness, and abuse of one type or another would follow. 

It was also depressing to watch the changing family dynamics. Children were increasingly not just undisciplined but completely unsocialised at the most basic levels by parents who cajole and bribe but set no discernible boundaries. This seemed to be especially true of white families; black kids were, on the whole, much better behaved — in their case it's at the teenage stage when things seem to go wrong. 

There is no sense of there being a public sphere at all, and certainly no sanctions against selfish or aggressive behaviour. Communal pressure is nonexistent and with it has gone any sense of shame. It has been deliberately dismantled. The cultural war waged by moral relativists and liberal self-haters has been hugely successful: they have trashed the place as effectively as any rioter. Authority, whether it be moral, social, familial or legal, has been chipped away at so relentlessly that it has finally collapsed. It is this, pure and simple, and not the tired excuses about disaffection and poverty, that has led so effortlessly to the burning of pubs and looting of shops. Many were shocked at the sight of eight-year-old rioters, but coming into Woolwich Arsenal late at night, I had got used to seeing small kids aimlessly milling about in front of the station, and the implied social anarchy.

Now fully multicultural after years of mass immigration, Woolwich no longer has an over-arching identity. For some time there has been a general air of social fragmentation, of different groups existing side by side but an absence of any collective sense. Certainly different cultures and religions make themselves felt — there are the halal butchers and Woolwich is home to the Greenwich Islamic Centre and mosque, founded in 1973 and which is currently undergoing major expansion. The Pentecostal, largely West African, New Wine Church has been in operation for more than a decade in the old Odeon cinema. 

The rioters, whatever their ethnicity, were doubtless almost all British-born. But mass immigration of the unprecedented type that London has seen over the past two decades, and which has had its effect in Woolwich too, certainly loosens if not destroys the natural ties that keep communities together and make things like riots less likely. Simple, small things confirm this: I carried out a little experiment of my own recently, before the rioting when, while in Powis Street, I asked directions to Wellington Street, one of the town's main thoroughfares, a couple of minutes' walk from where I stood. In central London, it would be like standing in Parliament Square and asking the way to Whitehall. Of the 11 passers-by I asked, just three knew  where it was and could help me.