The UK is on course to have its second female prime minister as Theresa May and Andrea Leadsom begin the task of winning the votes of Tory members around the country.
Around 150,000 Conservative members will decide the identity of the party's new leader - who will also take the keys to Number 10 - with the result to be announced on September 9.
Mrs May claimed a decisive win in the ballot of Conservative MPs which saw Michael Gove eliminated from the contest after finishing in third place.
The Home Secretary received 199 votes - well over half of the 330 Tory MPs - while Mrs Leadsom won the backing of 84 MPs and Mr Gove just 46.
Endorsement from The Sun
The contest between Mrs May and Mrs Leadsom will mean that the country will have a female premier for just the second time, following Margaret Thatcher.
Mrs May's campaign received a boost with an endorsement from The Sun newspaper - which proclaimed on its front page that the "new Mrs T must be Tezza not Leadsom".
She also won the support of Education Secretary Nicky Morgan, who had previously backed Michael Gove, and the leader of the Scottish Conservatives, Ruth Davidson.
But Ms Davidson called for Mrs May to guarantee that European Union migrants in the UK should be allowed to remain after Brexit.
"She says that she wants to be able to guarantee them and see guarantees for Brits living abroad in the EU. I actually want her to do one without the other," Ms Davidson told BBC Two's Newsnight.
Following the bruising EU referendum campaign and the resignation of David Cameron, the Home Secretary has insisted she can unite the party.
Mrs Leadsom was a prominent Brexit-backer and hopes that her support for leaving the EU will win her votes from Eurosceptics in the Tory grassroots.
After the result of the MPs' ballot was announced, Mrs May - who backed a Remain vote but kept a low profile during the campaign - said she could offer "strong, proven leadership" to negotiate the best Brexit deal for Britain and vowed to "unite our party and our country".
'Quirky' choice for the Tories
Mrs May said she had won support from MPs from across the party "left and right, leavers and remainers", while her supporters pointed out that Mrs Leadsom's support was mainly drawn from the Brexit-backing wing.
Mrs Leadsom's campaign chief Tim Loughton said the run-off represented a "quirky" choice for the Tories.
"They both went to state schools, they are both women, hey, that's pretty quirky for the Tory party. Isn't this the new sort of Tory party?"
Former Tory leader Iain Duncan Smith, who is backing Mrs Leadsom, said she had "steel" but within the "velvet glove of compassion".
Speaking to reporters outside Parliament he said: "I believe Andrea now, going to the country, has all that fantastic combination of steel, real grit, real determination, real world experience - working 25 years out of this place (Parliament), setting up charities - and in government she has that experience.
"So I believe all that compassion will come through and people will warm to her and I believe she will win."