More than 100 Tory MPs are expected to back scrapping the ban on new grammar schools as a campaign launches this week to secure the change now Theresa May is in Number 10.

Conservative Voice, a Tory activist group launched by David Davis and Liam Fox in 2012, will formally restart its grammar schools campaign on Tuesday.

They will be writing to Mrs May and her new Education Secretary Justine Greening, holding events in Parliament and across the country and launching a social media drive to build up pressure.

The move comes after Ms Greening said she is “open minded” about allowing new grammar schools to open in England in a marked change in tone from David Cameron’s government.

Senior backers of grammar schools including Mr Davis and Mr Fox are now sat around the cabinet table while other frontbenchers have expressed support for expansions in their constituencies.

Campaigners believe now is their best chance for a generation of overturning Tony Blair’s block on the creation of new English grammar schools, enshrined in a law created in 1998.