The police don't have any respect in London especially from people that have nothing to lose.
And there you have the problem in a nutshell -- these people have nothing, and have nothing to lose. Unfortunately not everyone is able to pull themselves out of poverty; we on this forum have the luck to be intelligent enough to be useful and therefore can make a good living. Not everyone is as lucky to be a smart as we are.
Last time I checked the figures (earlier this year) there were twice as many unemployed people as there were jobs to be filled; so even if they hadn't given up hope, there would still be a lot of unemployed people with no money. Saying "I managed to get out, so can anyone else" just doesn't cut it.
We've created a society where there is a large influence of materialism and 'aspirational lifestyle'; making everyone essentially aspire to own stuff. And we're surprised when the poor turn to theft to fulfill this aspiration?
I remember not having money, and being around other people with no money, and how easy it was for the resentfulness and bitterness to creep in. If there had been riots at that time in my life, there would have been the temptation to let the anger take over, but I like to think that I would have taken the moral high-ground.