Hutton cites new research by the Sutton Trust revealing a third of all admission to Oxbridge came from 100 schools, all but two of which are private.
In particular, the top private schools did massively better than their exam results should predict.
This social stratification is now hardening.
Of course, Hutton is not recommending banning private schools. But I am... if you want to know why scroll down banning private schools.