Former skills minister Nick Boles has quit the government and vowed to return to the backbenches as the MP for Grantham and Stamford, while David Cameron prepares to visit The Queen at Buckingham Palace to resign as prime minister. Outgoing Home Secretary Theresa May will be appointed to the top job in British politics by the monarch this evening and a cabinet reshuffle is expected to follow.

Boles had briefly served as Michael Gove's campaign manager for the Conservative leadership contest until the Justice Secretary was beaten by fellow Brexit backer Andrea Leadsom and May onto the final ballot. The 50-year-old apologised to Gove after sending an anti-Leadsom email to Tory MPs, designed to drum-up support for Gove.

"What if Theresa stumbles? Are we really confident that the membership won't vote for a fresh face who shares their attitudes about much of modern life? Like they did with IDS," the document reportedly said.

Boles, who was first promoted to government by Cameron in 2012, thanked the outgoing prime minister for the opportunity and congratulated May on becoming his successor. "I have greatly enjoyed my time as minister for skills and minister for planning," he said in a statement.

"I take particular pride in three things: the introduction of the apprenticeship levy which will encourage more employers to offer apprenticeships and increase spending on apprenticeship training by £1bn a year by 2020; the development of the government's Skills Plan which heralds a transformation in the status and quality of technical education in England; and the introduction of permitted development rights which have made it possible to convert thousands of under-utilised offices and agricultural buildings into desperately needed housing.

"I would also like to congratulate Theresa May on becoming Prime Minister. I am very proud to be a member of the party that has now elected two women to hold this office. I look forward to giving her my full support as she strives to make Britain a place that works for everyone, not just a privileged few. It is a noble ambition and I wish her well."

Boles is the first resignation ahead of May's appointment and more manoeuvres, including sackings, are expected over the coming week. There has been much speculation in the British press over the future of current Chancellor George Osborne, who served as a close ally to Cameron and played a prominent role in the unsuccessful Remain campaign ahead of the EU referendum. Foreign Secretary Philip Hammond has been tipped as his replacement, with Osborne taking on Hammond's portfolio.