Boris Johnson, Jeremy Hunt, Dominic Raab, Michael Gove, Andrea Leadsom and Matt Hancock are the top contenders
The race to replace Theresa May as British prime minister already has eight contenders vying for the top job.
Here is a look at some of the top names.
A former mayor of London, 'Boris' or 'BoJo,' said Friday he would get Britain out of the European Union 'deal or no deal.'
A key figure in the 2016 Brexit campaign, he failed in a bid for the top job in its aftermath as ally Michael Gove withdrew his support at the last minute.
May appointed Johnson as foreign minister but he quickly drew attention for the wrong reasons, including a series of diplomatic gaffes.
He became increasingly uncomfortable with the government's Brexit strategy before resigning in July.
Charismatic and popular with grassroots Conservatives, he has maintained his public profile by writing a weekly column in The Daily Telegraph.
Report: The race to replace Theresa May as British prime minister opened on Saturday with more contenders joining a crowded field vying for the top political position.https://t.co/D8f74mLmwW— TIMES NOW (@TimesNow) May 25, 2019
The foreign minister supported remaining in the European Union in the 2016 referendum but has been highly critical of what he calls the 'arrogant' approach since taken by Brussels.
A former businessman who speaks fluent Japanese, he is a resilient politician, having headed up the National Health Service for six years during a funding crisis.
The 52-year-old replaced Johnson as Britain's chief diplomat last year.
He has said he will push hard for a new deal with Brussels without taking the possibility of a no-deal outcome off the table.
An ardent eurosceptic with a black belt in karate, the 45-year-old quickly climbed the ministerial ladder after only joining the government in 2015 under former prime minister David Cameron.
He backed Brexit and was named justice minister in the new cabinet after the 2016 referendum.
Raab later served as Brexit secretary from July to November 2018, when he stepped down in protest at the Brexit deal struck with the EU by May.
Announcing his candidacy in The Mail on Sunday, Raab wrote that Britain should be ready to walk away from the EU without an agreement while still trying to negotiate a better deal that the one May signed.
Britain must "calmly demonstrate unflinching resolve to leave when the extension to negotiations end in October -- at the latest", Raab wrote.
Brexit campaigner Gove initially supported Johnson's leadership bid in 2016. His last-minute decision to enter the race himself caused both men to lose out to May.
"Whatever charisma is, I don't have it," he admitted in the race in which he came third.
After a year in the political wilderness, he was appointed environment minister in June 2017 and has stayed in the headlines with a series of eco-friendly policy announcements.
Equally active in his previous justice and education briefs, the cerebral 51-year-old was among the most ardent eurosceptics left in May's government.
Gove confirmed his intention to run on Sunday, saying he would aim to unite the party and the country and deliver on Brexit.
Former leader of the House of Commons Andrea Leadsom, who lost out to May in the 2016 contest to replace Cameron, stole a march on her rivals by quitting her cabinet position on Wednesday, hastening the prime minister's demise and staking out her pro-Brexit credentials.
She got down to the final two in the 2016 race, but pulled out before the decision was handed over to party members, with whom she was popular, after coming under fire for saying that being a mother would give her an advantage as prime minister over childless May.
The 40-year-old health secretary is one the party's rising stars, a moderate who is widely seen as competent at his job and skilful at handling the media.
He is one of several ministers who opposed Brexit during the 2016 referendum before switching sides and defending the withdrawal agreement May struck with the EU.