Eight Members of Parliament are battling for backers in their race to replace Boris Johnson as Tory leader - and Prime Minister.
Rishi Sunak is the early frontrunner and is likely to battle it out against one other contender in a vote by Conservative Party members.
Contenders for that coveted second spot include Jeremy Hunt, Penny Mordaunt, Liz Truss, Nadhim Zahawi and Kemi Badenoch.
But some of the hopefuls will be knocked out before the contest even begins, with the Tories’ 1922 Committee discussing a tough threshold to get on the ballot.
MPs could set a minimum 20 backers for each contender before the first knockout vote by MPs. There could also be a threshold of 36 votes to get through the first knockout round.
After that, MPs will vote in rounds, with one candidate being eliminated from the ballot each time until only two are left to put to the wider membership.
Boris Johnson has refused to publicly back any of the people who want to succeed him because it might hinder their chances. The winner will be announced on 5 September.
Business Secretary Kwasi Kwarteng is backing Liz Truss while key ex-Cabinet ally Michael Gove has backed Kemi Badenoch, the only black woman in the race. But her lack of experience and virtual anonymity means she won’t make the final two.
The 42-year-old MP for Saffron Walden - who was among those to resign their government jobs last week - said she would lower taxes, but also have a “tight spending discipline”.
During her time as equalities minister, Badenoch was criticised by the government’s LGBT+ advisory panel recently over delays in banning conversion therapy.
Nor is she popular in the black community. Badenoch condemns identity politics and “social justice”, particularly that based around race and culture, a common theme of her political discourse.
She is a former banker, who grew up in the UK, US and Nigeria. She has faced previous criticism for her overtly trenchant views on cultural issues, particularly her belief that racial disparities are often overplayed and not structural, and are exploited for division by left-wingers.