Nick Timothy has resigned at Theresa May’s joint chief of staff in the wake of a general election which saw the Conservatives lose their majority.

The advisor was a key figure behind the prime minister’s push to create new grammar schools, and allow existing grammr schools to expand.

His role behind the scenes was highlighted by the Spring newsletter of the Grammar School Heads’ Association, which revealed that he had met with them.

Mr Timothy did not mention grammar schools in his resignation statement, but his departure makes it more likely the policy will be dropped by the government.

Since 1998, there has been a legal ban on creating new grammar schools, and new legislation would be needed to reverse this.

The Conservative manifesto promised to lift the ban, but Theresa May’s loss of seats had already made it unlikely that it could pass the House of Commons, even if the Tories won the formal backing of the pro-grammar Democratic Unionist Party.

Mr Timothy had previously run the New Schools Network, which supports the creation of new free schools.