For the last three days I have been tuned to radio and television reports of the riots across London, which ignited in Tottenham on Saturday night and have been spreading in copycat outbreaks ever since.
As a Londoner I am ashamed and worried that images of wanton arson and destruction by feral youths in my city are being broadcast across the world.
What began as a legitimate and peaceful protest about the shooting of Mark Duggan by police - and the shabby treatment of his family in the wake of the killing - has been seized on by disaffected youngsters to cause mayhem.
Prepared to put lives at risk, they are obviously beyond the control of their parents, but it is to be hoped they are still within the reach of the long arm of the law.
With the original cause forgotten, the mob has used social media to organise confrontations with the police, loot, and lay waste where they can.
I haven't heard a convincing explanation for the riots. The measured police reaction, which is being criticised in some quarters, is working to contain the anger. No doubt the police will be using video evidence to make arrests once the dust has literally settled.
When the inevitable investigations are completed the causes of the disorder are likely to be seen as manifold. Social deprivation, family breakdown, gang and criminal culture, educational underachievement, and unemployment will probably all be in the frame.
I'm not going to prejudge to what degree race is an influence or whether class rather than skin colour was a major component. Areas that have seen some of the worst rioting had made the greatest efforts to bridge racial divides.
Boredom is likely to be a strong factor - the adrenalin rush that accompanies the challenge to authority, the buzz from smashing plate glass, reinforced by the prospect of a new pair of trainers. There may have been some knock-on impact from the Government's cuts; outside troublemakers, anarchist or otherwise may have fuelled the hot spots.
Whatever the lessons, they need to be learned quickly. The Notting Hill Carnival is just a few weeks away, a spectacular event but already one with a history of occasional after-dark crowd trouble. More importantly a year from now London will host the 2012 Olympics.
The last thing the police need is have a repeat of the riots at the same time as undertaking its duties to protect visitors and competitors to the Games.
The Met has been rattled on finding itself drawn ever further into the News of the World phone hacking scandal. A Commissioner to replace Sir Paul Stephenson has to be appointed as a matter of urgency; and it's probably a good idea to put manpower cuts on hold until at least after the Olympics.