If you've been on Twitter much since late yesterday trying to stay abreast of the disorder in London - and possibly even if you haven't - you'll be thoroughly familiar by now with the opposition: mere criminality / a reflection of alienation, exclusion etc. Criminality there certainly is and anyone who fails to register this is deluding him or herself and possibly others. But if it were just criminality it would be less worrying than it is. What has horrified so many people, apart from the recklessness and the callousness involved in the actions of the rioters, is the threat to civil order and the seeming inability of the police to contain it. On the other hand, though various grievances may well be at work here, they can't be construed as a sufficient cause of what is happening since such grievances might have been channeled otherwise and more positively.
The most interesting paragraph I've read about the situation comes from Kenan Malik, who tries to move beyond the opposition criminality / result of social exclusion.
There is clearly more to the riots than simple random hooliganism. But that does not mean that the riots, as many have claimed, are protests against disenfranchisement, social exclusion and wasted lives. In fact, it's precisely because of disenfranchisement, social exclusion and wasted lives that these are not 'protests' in any meaningful sense, but a mixture of incoherent rage, gang thuggery and teenage mayhem. Disengaged not just from the political process... there is a generation (in fact more than a generation) with no focus for their anger and resentment, no sense that they can change society and no reason to feel responsible for the consequences of their actions. That is very different from suggesting that the riots were caused by, a response to, or a protest against, unemployment, austerity and the cuts.