Six Conservative MPs are still in the race to be the next Tory leader and prime minister.
Here are the candidates who will battle it out in the second round of voting on Tuesday.
Ballots continue this week until two remain, when members of the wider Conservative Party will then get a chance to vote for their preferred choice.
Candidates for Tory leadership
Boris Johnson topped the first leadership poll with 114 votes. He did not take part in the first televised debate on Channel4, leaving the other five to battle it out, alongside an empty lectern.
The former mayor of London, who has long coveted the top job, says he will take part in the live debate on the BBC, after the second round of voting.
Mr Johnson, a leading Brexiteer, had been at odds with Theresa May’s Brexit vision for some time before he eventually quit as foreign secretary in protest over it last year.
The MP for Uxbridge and South Ruislip has been a loud and prominent critic of Mrs May and her policies ever since. If he becomes leader, the UK will leave the EU on 31 October "deal or no deal", he has said.
The Eton and Oxford-educated former political journalist is a popular figure with members of the wider Conservative party.
Jeremy Hunt scored 43 votes in the first leadership poll.
The foreign secretary campaigned to remain in the EU during the 2016 referendum, but has since been reborn as a Brexiteer.
He even suggested, to widespread criticism, that the EU was like the Soviet Union. However, he has said his party would be committing “political suicide” if it tried to push through a no-deal Brexit.
An MP for South West Surrey since 2005, Mr Hunt was made culture secretary under the coalition government in 2010 and oversaw the 2012 London Olympics before becoming health secretary.
In 2018, he became the longest-serving health minister - and arguably one of the most controversial - since the NHS was created, completing six years in the role. During his tenure, he clashed with unions over contracts for junior doctors, who took part in a series of walkouts in 2015.
Michael Gove scored 37 votes in the first round of voting by Tory MPs.
Mr Gove, who led the Vote Leave campaign in the 2016 EU referendum, has been forced to address questions surrounding cocaine use. He said it was a mistake and he deeply regretted taking it at social events 20 years ago, while working a as journalist.
The MP for Surrey Heath, since 2005, was a key ally of former Prime Minister David Cameron. He made his name as a radical education secretary, bringing in major changes to exams and the curriculum and battling teaching unions during his four years in the role.
In 2016, he famously scuppered the leadership hopes of his friend and fellow Brexiteer Boris Johnson, by announcing his own candidature on the morning Mr Johnson was due to launch his campaign.
Mr Gove became environment secretary in June 2017 and he proved a key advocate of Mrs May’s Brexit deal, while other Brexiteer cabinet ministers resigned.
Dominic Raab scored 27 votes in the first round of voting.
Mr Raab, who has been tipped for high office since his election as an MP for Esher and Walton in 2010, has insisted that Brexit must happen on 31 October whether there is a deal or not.
He has refused to rule out shutting down - or proroguing - Parliament as he says it could be necessary to deliver Brexit.
The former lawyer was appointed as a justice minister in 2015, but was sacked by Theresa May when she became prime minister the following year.
After David Davis’s resignation as Brexit secretary in July 2018, Mr Raab was appointed as his successor. He quit only months later in opposition to Theresa May’s Brexit deal, which he said he couldn’t “in good conscience” support.
Sajid Javid scored 23 votes in the first round of the leadership contest.
The home secretary launched his leadership bid with a pledge to “rebuild trust and find unity”. Mr Javid backed Remain in the 2016 EU referendum, but with a “heavy heart and no enthusiasm”. He has never hidden his Eurosceptism.
Born in Rochdale, Mr Javid is a second-generation migrant whose parents came from Pakistan - he says his bus driver father arrived with only £1 to his name.
A former protégé of former chancellor George Osborne at the Treasury, he was a successful investment banker before he was elected as an MP for Bromsgrove in 2010.
International Development Secretary@RoryStewartUK
Rory Stewart scored 19 votes in the first leadership poll.
Mr Stewart was promoted to international development secretary, his first cabinet role, in May, having previously served as prisons minister.
Although he campaigned for the UK to remain in the EU during the 2016 referendum campaign, he said he accepted Brexit, saying: “I am a Brexiteer.”
He said he also wanted “to reach out to Remain voters as well to bring this country together again”.
Before he was elected as the MP for Penrith and The Border in 2010, he had a varied career as a Foreign Office diplomat, an author and a professor at Harvard University.
Candidates had to have the backing of 17 MPs to make it through the first round.
Boris Johnson won the most votes - with 114, followed by Jeremy Hunt with 43.
Mark Harper, Andrea Leadsom and Esther McVey were eliminated after failing to get the necessary 17 votes.
Matt Hancock, who won 20 votes, later withdrew from the contest, pledging his support for Boris Johnson.
But where do the potential new prime ministers stand on key issues?
Here's a quick guide to their positions on Brexit, Tax and spending, and Health and Education.
Compare candidates' policies
Select a topic and a candidate to find out more
- Has said he would consider a further delay to Brexit to achieve a better deal.
- Plans to negotiate a "fullstop" to the Irish border backstop plan. He wants a free trade agreement, similar to the deal between Canada and the EU.
- Would support a no-deal Brexit if he couldn't get a better deal from Brussels.
- Would leave the EU with no deal, but it's not his preferred option.
- Wants changes to the Irish backstop and proposes sending a new negotiating team to Brussels.
- Wants to make changes to the Withdrawal Agreement and thinks it's possible to get them done by 31 October, but has not ruled out an extension.
- Would focus on making changes to the backstop. Would commission UK border force to work on solving the Northern Ireland border problem, paid for by the UK.
- Says he cannot envisage circumstances in which he would want to have another extension to the UK's exit date and the country must be prepared for a no-deal Brexit.
- Wants to leave on 31 October, the deadline for Brexit set by the EU, with or without a deal. He admits a no-deal exit will cause "some disruption" but says the "way to get a good deal is to prepare for no deal".
- Wants to remove the backstop from any deal and replace it with "alternative arrangements".
- Says he would withhold the £39bn "divorce" payment the UK is due to give the EU as part of the negotiated deal. He says the money will be retained until there is "greater clarity about the way forward".
- Wants to re-open the withdrawal agreement for renegotiation in order to "overhaul the backstop".
- Says a new deal would include "the vast majority" of the deal Theresa May negotiated, but would replace the Irish backstop with "alternative arrangements" involving "advanced customs and trade measures" and checks away from the border.
- Willing to leave on WTO rules, claiming it is "far better than leaving with a fatally flawed deal", and will not rule out proroguing Parliament (essentially shutting it down) ahead of the 31 October deadline to prevent it blocking a no-deal Brexit
International Development Secretary
- Believes a no-deal Brexit would be "catastrophic" for the UK and is "undeliverable" and "unnecessary".
- He said it was unrealistic to believe the UK could get a new Brexit deal agreed by the EU and Parliament by the 31 October deadline.
- Prefers trying to push through the current deal, agreed by Theresa May. However he says, if that failed, he would set up a jury of citizens to thrash out a compromise.
TAX AND SPENDING
- Says he wants to replace VAT after Brexit with a lower, simpler sales tax.
- Wants to create the "most pro-business" tax regime in the world and put business at the heart of the revival of Britain.
- Says he would not use the tax and benefits system to give the already wealthy another tax cut.
- Says he would scrap the High Speed rail 2 project.
- As an entrepreneur, he wants to turn Britain into the next Silicon Valley, a "hub of innovation".
- Pledged to slash business taxes to the lowest in Europe to attract firms to Britain after Brexit and reduce corporation tax.
- Has promised to break from the austerity of the past nine years by slowing the pace of debt reduction.
- Says this would free up about £25bn a year for spending priorities, including education.
- Other money would be spent on local government and efforts to tackle crime, including an increase in the number of police officers by 20,000.
- Pledges to cut income tax for people earning more than £50,000 by raising the 40% tax threshold to £80,000.
- Says it will benefit three million people and would cost £9.6bn a year.
- Plans to pay for the cut partly from a pot set aside by the Treasury for a possible no-deal Brexit, and partly by increasing employee National Insurance payments.
- Wants to cut the basic rate of income tax from 20% to 15%. He suggests the basic rate falling by a penny a year.
- Would equal a tax cut for the majority of UK workers. HMRC says there are currently 26.3m basic rate tax payers, but IFS says it costs about £5bn for every 1p cut in the rate of income tax.
- Wants to raise the point that people start to pay national insurance to be the same as income tax, £12,501 a year. He says it would save the lowest paid workers £460 a year.
International Development Secretary
- Criticises other candidates for offering "cheap electoral bribes" to win support.
- Says rather than being "straight" with people, his opponents have pledged "eye-watering" tax cuts worth £84bn.
HEALTH AND EDUCATION
- Says he wants to ensure the NHS is "fully-funded, properly funded" and that funding is protected under law.
- Says he will spend £1bn extra on schools if he becomes prime minister.
- Mental health support in every school and a crackdown on social media companies that fail to regulate their content.
- A cut in interest rate paid on tuition fees.
- Long term plan to provide more funding for the teaching profession in return for a guarantee that no one leaves the education system without a "rigorous qualification" sufficient to work up to at least the average salary.
- Has suggested slowing down the rate of debt reduction, to release money for education.
- Wants to see a "multi-year, multi-billion-pound boost" to spending on schools to "change the life chances of so many young people".
- Promises to raise spending on secondary school pupils to £5,000 each.
- Called the funding gap between some schools in cities compared to those in rural areas a “disturbing reality”.
- Has previously said money spent on the EU could be put into the NHS.
- Says he is in favour of bringing back young apprenticeships for 14-16 year-olds.
- Wants review of spending in Whitehall, with a “special commission” to look at public sector procurement, especially in the NHS.
- Says he would “recycle roughly half” of the savings made by the spending review into frontline services, such as teachers and nurses.
International Development Secretary
- Pledges to invest more into education, especially for those in “mid-life”.
- Vows to put a long-term plan in place to tackle the issue of social care in the UK.
- Says people should not have to pay hospital car parking charges to visit a sick relative or wait four weeks for a GP appointment.
The popularity of individual candidates among the wider party members differs slightly to the ranking produced by the MPs' first-round vote.