Schools are already selecting by wealth, with poor children twice as likely to attend substandard secondary schools, a study has found.

Just one in six of those from the poorest families win places at the best primary schools, according to research by the charity Teach First which found that the gulf between rich and poor children grows even wider by the time they reach secondary school.

The findings will viewed as supportive of Prime Minister Theresa May’s assertion that a new generation of grammar schools will help the brightest children from disadvantaged families to achieve their potential at good schools, in a system of where students are selected on ability rather than on wealth.