The selective schools are expected to be required to admit a large number of pupils on free school meals MATTHEWLLOYD/GETTY

Plans for new grammars will amount to only about 20 selective schools in working class areas, it was claimed yesterday.

Theresa May has been tipped to overturn a ban on new grammar schools, after pledging in her first speech as prime minister to tackle social mobility. A Whitehall source said that the new selective schools would be sited in a handful of “typical working-class areas”, such as the outskirts of Birmingham and other provincial cities.

Birmingham is the home town of Nick Timothy, one of Mrs May’s special advisers, who is thought to be the driving force behind the push for grammar schools. He was formerly the director of the New Schools Network, which advises groups setting up free schools.

“It is unlikely they will…