I have recently contended in an article (here) that the London Riots of the summer of 2011 were the cause of a perceived lack of opportunities for upward mobility. I contended that policies that raise the cost of living (zoning laws, import duties, regulations on businesses) are combined with policies that reduce the possibilities of employment as well as the rewards of employment. I put considerable emphasis on the perverse effects of occupational licensing and its rise in the United Kingdom.
There is considerably litterature on the issue of occupational licensing in the United States (where nearly 30 % of occupations are subject to licensing) and the possible effects it has on low skill labour (mostly uneducated natives and African-Americans). There is less data available on the case of the United Kingdom, but the little data we do have does point to a steady rise in the number of jobs being more tightly regulated through licensing (see graph below derived from this paper)