Liz Truss will become the next prime minister after defeating Rishi Sunak in the Conservative Party leadership contest.
Ms Truss, who was the favourite to win the contest, will succeed Boris Johnson on Tuesday and become the nation's third female leader.
She secured just over 81,000 to Mr Sunak's just over 60,000.
Mr Johnson, who was forced to announce his resignation after a wave of ministers left his government over a series of controversies, will visit the Queen at Balmoral Castle in Scotland to formally tender his resignation.
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Shortly after this, Ms Truss will also meet the Queen, who will invite her to form a government.
Ms Truss is expected to make a speech outside Number 10 once she takes office and will then get to work on appointing her cabinet.
She faces the immediate challenge of coming up with a package of support to help households weather a worsening cost of living crisis driven by soaring energy bills.
Ms Truss has promised big tax cuts to boost economic growth, including reversing the rise in National Insurance.
Mr Sunak and Ms Truss were whittled down to the final two candidates after five rounds of voting by Tory MPs.
The pair went head to head over a summer of hustings and live television debates, during which they clashed repeatedly over their plans for the economy.
Party members had from 1 August to 2 September to cast their votes, which were counted over the weekend.
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