It's a bit of a big issue for me to explain and, quite frankly, my procastinating ass can't be bothered (not to mention that I'm not that good at explaining to begin with) so I'll just link this -
http://www.bbc.co.uk/news/magazine-14483149It doesnt give all the potential reasons, and just skims those that it does, but it does provide some actual explanations instead of conjecture.
Education, occupation & income.
They are given all of these. At the expense of tax payers.
They choose not to improve their lives because their lives at the moment are far too comfortable.
The red areas represent the most socially deprived areas. The darker the red, the worse they are. The Volcanos represent where the riots have been. Coincidence?
The survey itself comes from a government report,
found here, which give a viable source for discontent not just in London, but around the country in other riot-hit cities. Their lives are anything but "comfortable".
Oh, and heres another report on the correlation between austerity measures and anarchy:
clicky. Make of it what you will.
P.S that documentary series looks quite interesting Archie, thanks.