The first thing I read this morning was a rant by one of my cousins on Facebook against the people rioting in London. As far as I can tell a lot of people are cashing in on the opportunity to steal things or to bash the government or to bash the left. This seems like a fairly sensible assessment from my perspective, an ocean away. I can't find it now, but as I recall the Telegraph ran a piece attacking the left for blaming the riots on the government "as they inevitably would," i.e. before anyone had actually done any such thing. That was pretty disgusting. But then people on the left did start trying to connect the riots to government cuts.
I have little to say on the subject, but I think it is always a bad idea to try to identify what the cause is with events like this, or what it is that they are really about. Wars and riots are wars and riots. They are not parables. They are not necessarily about anything. Nor are they simple events with simple causes. Many people are involved, each possibly with several different motivations. These might include righteous anger, self-righteous anger, greed, boredom, a desire to be part of history, a desire to go along with one's peers, and much else besides. Of course these things are not the norm, so it isn't unreasonable to ask why these riots happened where they did, when they did. But the answer is likely to involve a combination of factors, not just one key event that we can identify and load all our blame onto.
Secondly, it's generally a good idea when possible to separate reasons from causes. Most rioters are not likely to have good reasons to burn, loot, and attack people. But seeing this fact does not require us to ignore possible causes of criminal behavior at the economic or social level. Tony Blair's idea of being tough on crime and tough on the causes of crime isn't so stupid (even if people who want to be "tough on crime" often favor bad ideas). (These causes are hard, if not impossible, to identify, but it's always possible to use trial and error. If egalitarian moves are followed by less crime then it might be a good idea to support such moves, and if movements in the other direction are followed by more crime then it might be good to oppose such movements. This looks like a case of nineteenth-century-style, laissez faire liberal policies leading to the kind of behavior that motivated the twentieth-century reforms that the right is trying to undo. But I really know so little about political and economic history that I probably shouldn't risk making such claims at all.)