Liz Truss and Rishi Sunak will vie to be next Conservative leader and Prime Minister in the final round of the Conservative leadership.
Former Defence Secretary Penny Mordaunt was knocked out on Wednesday after a bitter contest in Westminister.
The former chancellor and the Foreign Secretary finished in the top two places after five rounds of voting by Tory MPs.
Mr Sunak received 137 votes in the final round of voting, while Liz Truss won 113 votes, which narrowly pushed Ms Mordaunt into third place on 105.
The two remaining candidates will face a campaign to win the votes of Tory members, with the final result of the contest announced on September 5.
The winner is expected to replace Boris Johnson as prime minister the following day with Mr Johnson expected to hand in his official resignation to The Queen on September 6.
Ms Mordaunt came in second in all previous rounds of voting, but a late surge by Ms Truss cost her a place on the ballot.
The Foreign Secretary gained 27 votes, Mr Sunak put on 19 while Ms Mordaunt could only gain an extra 13 supporters.
Mr Sunak’s campaign said he had secured a “clear mandate” from Tory MPs and will now “work night and day” to win the backing of the Conservative membership.
The statement said: “The choice for members is very simple: who is the best person to beat Labour at the next election? The evidence shows that’s Rishi.”
Meanwhile, Ms Truss said: “I am excited to now take to the country to make the case to the Conservative Party about my bold new economic plan that will cut taxes, grow our economy and unleash the potential of everyone in our United Kingdom.
“As Prime Minister I would hit the ground running from day one, unite the Party and govern in line with Conservative values.”
The two candidates are expected to go head to head in a TV debate on Monday night and take part in a series of hustings.
Previous debates saw them fiercely clash with each other and some Tories fear the damage further public rows will cause to the party.
Ms Mordaunt congratulated her two rivals and said: “I pay tribute to anyone who puts themselves forward for such a demanding role.
“Politics isn’t easy.
“It can be a divisive and difficult place.
“We must all now work together to unify our party and focus on the job that needs to be done.”
Next Conservative leader odds
Betfair Exchange has released its odds on who will be the next Conservative leader, replacing Boris Johnson.
- Liz Truss: 4/6 (was Evens on Wednesday morning)
- Rishi Sunak: 6/4
“It will be Liz Truss and Rishi Sunak going head-to-head to be the next Tory leader following Wednesday’s final Tory leadership ballot, Betfair spokesperson Sam Rosbottom said.
He added: "Odds on Liz Truss to replace Boris Johnson have been slashed to 4/6 from Evens since the ballot results, while Sunak is 6/4 to move into No.10.”
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