How does the process work?published at 08:44 British Summer Time 10 June 2019
Candidates wanting to be chosen for the leadership have to first secure more than eight MPs' signatures for their candidacy.
Those who are successful will then get through the first ballot of voting by Tory MPs on Thursday to start reducing the contenders down. There'll then be a succession of further votes and each time, the challenger with the fewest will be removed.
The final two candidates will then face a postal ballot of Conservative Party members to decide their future.
In the next six weeks, the party will have a new leader, and the country a new prime minister. Expect the next occupant of Number 10 to be in office in the week beginning 22 July.