Boris Johnson
The former mayor of London has long coveted the top job. He announced he would be standing, saying “Of course I’m going to go for it.”
Mr Johnson, the face of the Vote Leave campaign, quit as foreign secretary last year in protest at Theresa May's Brexit plans and has been a loud and prominent critic of her and her policies ever since.
He is popular figure with Conservative members, but has fewer fans in Parliament. His main task will be to convince enough Tory MPs to vote for him to get on to the ballot of party members.
He stepped back from the 2016 leadership fight after fellow Brexiteer Michael Gove launched his own campaign for a run at the top job.