Theresa May will stand down as Conservative leader on Friday, kicking off the official race to lead both the party and the UK.
Downing Street hopefuls are already lining up high-profile endorsements and policy proposals in what has become the most crowded contest in Tory history.
So what do they have to do to win?
Two proposers
Candidates currently need the backing of just two MPs to stand. Nominations for the contest are likely to close next week, at which point the final longlist can be announced and the candidates will launch their campaigns.
So far, 13 candidates have put their names forward. The contenders include five current secretaries of state: Environment Secretary Michael Gove, Foreign Secretary Jeremy Hunt, International Development Secretary Rory Stewart, Home Secretary Sajid Javid and Health Secretary Matt Hancock.
Also throwing their hats into the ring are five MPs who quit the Cabinet over May’s Brexit plans: former foreign secretary Boris Johnson, former House of Commons leader Andrea Leadsom, former Brexit secretary Dominic Raab, former work and pensions secretary Esther McVey and former universities minister Sam Gyimah.
The remaining three candidates are junior Brexit minister James Cleverly, Housing Minister Kit Malthouse and former chief whip Mark Harper.
MPs vote
In the first stage, Tory MPs must whittle down the large group of candidates to create a shortlist. “That will involve a number of hustings in Parliament and voting rounds that will see the contestants with the least support eliminated,” says PoliticsHome.
The party is aiming to complete this part of the process by the end of June.
Members vote
Next, Conservative members will vote for their preferred candidate, on a “one member, one vote” basis.
Under the current rules, there are only two leadership hopefuls on the ballot, but the 1922 Committee of Tory backbenchers and the party’s ruling board is considering doubling that number to four, reports PoliticsHome.
Candidates will pitch to members through hustings and may take part in live debates on TV. Members must have been registered for at least three months to take part in the election.
Conservative Party Chair Brandon Lewis says the new leader should have been chosen by the summer parliamentary recess, which is usually towards the end of July.
