Claims by Theresa May that grammar schools have proved to be great engines of social mobility have been undermined by figures showing that the vast majority of grammars admit only a tiny proportion of children from the poorest families.

As pupils return after the Christmas break, official figures show that in many grammar schools, less than 1% of the total pupil intake receives free school meals (an indicator of the poorest families). Only one of the 163 selective schools in England takes in more than 10% from this least well-off group.