Here is the link
to the study referred to by Melissa for being favourably reported in the Daily Mail. Published in the British Journal of Sociology, it is based on the fifty year long National Child Development Study, and paints a very different picture about the success of comprehensive education than the one we usually see. Authors Vikki Boliver and Adam Swift take head on the frequently made assertion that social mobility has stalled because of the abolition of the grammar schools. Instead they look overall at the effects of the comprehensive systems compared to grammar/secondary modern systems.
The conclusion states : "Rather than focusing on grammar schools, and on the children judged worthy of selection into them, any proper assessment of the effect of comprehensivization on social mobility must look at all children, comparing comprehensives with selective-system schools as a whole. Once we include secondary moderns in the analysis, our findings are simple and unambiguous. Comparing relevantly similar children, selective-system schools were no more conducive to mobility, whether upward or downward, whether between income quartiles or class categories, than were comprehensives. Any mobility advantage accruing to children from low-income or working-class origins who attended grammar schools was cancelled out by an equivalent mobility disadvantage
suffered by those who went to secondary moderns. In short, matching on relevant attributes, considering all types of social mobility (and immobility), and keeping in view all types of school, our findings suggest that comprehensive schools were as good for social mobility as the selective schools they replaced."