I'm a Londoner near some of the affected areas. The sky is not falling, London is not degenerating into lawlessness, and from what I can see from my flat window, police are responding quickly. Other areas may be different, but London is a very large city - commenters should remember that in discussions.
So what was the trigger that started the riots?
http://www.independent.co.uk/news/uk/crime/a-dead-man-a-cruc...
http://www.telegraph.co.uk/news/uknews/law-and-order/8687403...
http://www.guardian.co.uk/uk/2011/aug/08/mark-duggan-profile...