Here is a brief guide to the five Conservatives who will be standing for party leader.
:: Theresa May
A quiet Remain backer who is seen as a steady hand to calm the party after its post-Brexit turbulence. The current Home Secretary’s campaign will be run by Chris Grayling. The Maidenhead MP is seen as the favourite to succeed David Cameron.
She said: “My pitch is very simple. I’m Theresa May and I think I’m the best person to be prime minister of this country.”
:: Michael Gove
The Justice Secretary, who sparked controversy when he was handling the education brief, was at Boris Johnson’s side for much of the Vote Leave campaign.
Mr Gove appeared to be throwing his support behind Mr Johnson’s leadership ambitions, before performing an incredible about-turn and running himself, saying he did not believe Mr Johnson could “provide the leadership” the Tories needed. Only a three hours after the Gove statement Mr Johnson quit the contest.
:: Stephen Crabb
The Work and Pensions Secretary is hugely popular in the Conservative parliamentary party and comes from the sort of ordinary background that chimes with many voters.
The former Welsh Secretary says the party should be led by someone ‘’who understands the enormity of the situation we’re in and who has got a clear plan to deliver on the expectations of the 17 million people who voted to come out last week’’ including keeping the United Kingdom together.
:: Andrea Leadsom
An assured performance by the Energy Minister for the Brexit side in the referendum campaign won Ms Leadsom praise.
The former banker and fund manager announced she was in the running, tweeting: “Let’s make the most of the Brexit opportunities!”
:: Liam Fox
Dr Fox - who unsuccessfully sought the top job in 2005 - was the first to confirm he was considering a fresh bid. An outspoken supporter of Brexit, he would hope win over the right of the party.
The former defence secretary resigned from the front benches in 2011 after allowing his friend and best man Adam Werritty to take on an unofficial and undeclared role as his adviser.