Loud, colourful ex-mayor has had chequered career
He is the bookies' favourite to be Britain's next prime minister and receives wide support from members of his Conservative party.
But Mr Boris Johnson, the loud and colourful former London mayor and leading figure of the Leave campaign, who some say has slyly manoeuvred his way to a likely premiership, may find his path to Downing Street not a smooth one.
From being the country's most popular politician, the 52-year-old became the subject of boos and jeers from protesters outside his home the day the result of the referendum was announced.
Astounded by the vitriol and untruths that have marked Mr Johnson's campaigning in the run-up to the referendum last Thursday, and the division within the party that he has caused, some Conservative MPs have also launched a "Stop Boris" movement within the party by pushing for other candidates to step up to the plate.
That movement has spread beyond the party to Remain supporters who are urging people to join the Conservatives so they can vote in the upcoming election against Mr Johnson's bid for leadership.
Born in New York City to upper middle-class parents, Mr Johnson attended the elite Eton College and read classics at the University of Oxford, where he became president of the Oxford Union.
He started his career as a journalist at The Times but was sacked after he fabricated a quote in a story. The Daily Telegraph took him in and sent him back to Brussels as a correspondent. There, he wrote scathing stories about the European Commission.
Fellow correspondents criticised him for what they described as dishonest and irresponsible reports.
Tabloids have, on at least two occasions, exposed his affairs with two fellow journalists and he was sacked from the Conservative shadow Cabinet where he was arts minister. But that did not dim his star.
He was London mayor for two terms, from 2008 to this year, and took credit for projects such as the 2012 Olympic Games and the new railway line, Crossrail, both of which had started during the previous mayor Ken Livingstone's term.
Neither the public nor the media could get enough of his "buffoon-like" image, his quips and his ability to not take things seriously.
On Sunday, he broke his post-referendum silence by writing in The Daily Telegraph that Leave voters must "build bridges" with Remain supporters.
He said the only change is that Britain will "extricate itself from the EU's extraordinary and opaque system of legislation".
"There is every cause for optimism; a Britain rebooted, reset, renewed and able to engage with the whole world," he wrote.
No-nonsense leader who can make tough decisions
She has been compared to German Chancellor Angela Merkel: no-nonsense, reliable and with the ability to make tough decisions.
For the past six years, Ms Theresa May, 59, has been Home Secretary in the Cabinet of Prime Minister David Cameron, making her only the fourth woman to hold one of Britain's Great Offices of State - the four most senior Cabinet posts - after former prime minister Margaret Thatcher, former foreign secretary Margaret Beckett and former home secretary Jacqui Smith.
Ms May, whose father was an Anglican clergyman, was born in Eastbourne, Sussex. She studied geography at the University of Oxford and then joined the Bank of England, before becoming a financial consultant at the Association for Payment Clearing Services, a banking association that manages Britain's clearing systems. She was elected MP for Maidenhead on the Conservative ticket in 1997 and has held the education, employment and transport portfolios in shadow Cabinets.
In 2002, she was appointed the first woman chairman of the Conservative party. Looking after immigration, citizenship and national security, she has one of the biggest and toughest portfolios in government. Her policies have been controversial, such as those aimed at curbing immigration.
For instance, she introduced a £35,000 (S$65,000) minimum salary requirement for non-European Union workers who want to stay in the country after five years. She also implemented an £18,600 income threshold for British citizens who want to bring their foreign spouse or child to Britain.
Last year, she tabled an investigatory powers Bill in Parliament that will give security agencies powers to access records that track British citizens' use of the Internet.
Ms May maintained a low profile during the entire campaigning period for the European Union referendum, some say, so that should the Leave camp win, she would be well positioned to take a shot at the Tory leadership.
Although she publicly backs the Remain camp, she has sometimes been viewed as a eurosceptic. She believes Britain should quit the European Convention on Human Rights as it prevents Britain from deporting extremists and dangerous foreigners and therefore puts the country's security at risk.
She is the longest-serving home secretary in more than a century. There is already a movement within the party ranks to back Ms May - the most credible candidate among names that have been tossed up - among MPs who have no confidence in former London mayor Boris Johnson as a leader.