Liz Truss will become the country’s third female prime minister after securing victory in the Tory leadership contest.

She defeated rival Rishi Sunak with 81,326 votes to 60,399 and will take over as prime minister on Tuesday with the immediate challenge of easing the cost-of-living crisis for households across the country faced with soaring energy bills.

Ms Truss, the Foreign Secretary, used her victory speech to indicate she would not be triggering an early general election, instead pledging to secure “a great victory for the Conservative Party in 2024”.

She won by a significant margin, but the 57% victory over Mr Sunak’s 43% was slimmer than in other recent contests.

Ms Truss thanked her “friend” Boris Johnson, who will depart No 10 on Tuesday before Ms Truss flies to Balmoral to meet the Queen for the formal handover of power.

“Boris, you got Brexit done, you crushed Jeremy Corbyn, you rolled out the vaccine and you stood up to Vladimir Putin.

“You were admired from Kyiv to Carlisle,” she told the QEII conference centre in Westminster.

Ms Truss will quickly begin work putting together a response to the energy crisis, with support promised within days.

Labour leader Sir Keir Starmer said Ms Truss is “not on the side of working people” after she was unveiled as the new leader.

Giving his reaction to the result at Friern Barnet School in north London, he told journalists: “We’ve heard far more from the latest prime minister about cuts to corporation tax over the summer than we have about the cost-of-living crisis, the single most important thing that’s bearing down on so many millions of households.

“That shows not only that she’s out of touch, but she’s not on the side of working people.

“So she needs to deal with the cost of living crisis, she needs to deal with the fact the NHS is on its knees, and she needs to deal with the collapse of law and order.

“There can be no justification for not freezing energy prices.

“There’s a political consensus that needs to happen.

“She needs to ask the question how she’s going to pay for that.

“Labour made it clear, it needs to be a windfall tax on oil and gas companies.

“So, she needs to show that she actually understands and can meet the challenges that are there after 12 years of failure of this Tory Government.”