Well, increasing the police presence in London did reduce the problems to almost nothing. But, were the riots in Manchester, Salford, etc partially due to a reduced police presence there as officers had been sent to London?
I notice that it kicked off in Gloucester last night. Having lived there in the 70s, it suggests to me to that a lot of this violence has more in common with the football related violence of the 70's and early 80's, than incidents like the Brixton and Toxteth in the 80's. And I'm not really surprised that copy-cat looting and violence broke out there!
What could be considered more worrying is the rise of groups of people on the street defending commercial properties and homes from potential rioters. Were this is local shopkeepers and residents this is understandable (if a little worrying - shouldn't the police be doing this and will it lead to the 'defenders' using excessive force and getting arrested?), but what is scary is the fact that members of the far right English Defense League (who Anders Behring Breivik claimed allegiance with) have been turning up (after drinking heavily according to some sources) in order to 'defend*' certain areas.
Any involvement of far right groups is only going to end badly, and lead to a rise in vigilantism (not a good thing).
* For defend read 'cause racially motivated violence'