Britain will have its third prime minister in less than three years, with the ruling Conservative Party announcing Monday that Liz Truss had been chosen as its new leader following an internal party contest.

Truss succeeds Boris Johnson, a divisive figure who defied many of Britain’s political traditions. Johnson resigned in July after senior members of his government turned against him amid a series of scandals involving his own coronavirus lockdown rules and dwindling support for his populist politics.

Because Britain elects a party rather than a specific leader, the ruling party has some leeway in appointing a new prime minister. Truss was chosen by approximately 172,000 Conservative Party grassroots members. That figure represents less than 1% of the U.K.’s 67 million population.

The new prime minister takes office on Tuesday, as household energy bills in the United Kingdom reach unsustainable levels for millions of people.

Truss received 81,326 votes to Sunak’s 60,399 votes, or 57% to 43%.

Truss, 47, has sought to position herself as the political heir to Margaret Thatcher, Britain’s “Iron Lady” and first female leader who zealously advocated for free markets, lower taxes, and the privatization of large state enterprises ranging from telecommunications to energy. Truss was a member of Johnson’s cabinet, first as trade minister and then as foreign secretary. She has taken a tough stance against Russia in response to its invasion of Ukraine.

“A belief in small government runs through Truss’s career,” Daniel Hannan, a former Conservative party politician, wrote in an opinion piece published on his website. Hannan is now known in the House of Lords as Lord Hannan of Kingsclere, the unelected upper house of Parliament to which Johnson appointed him.

Sunak, 42, was finance minister in Johnson’s administration, where he oversaw a multibillion-dollar coronavirus support package for businesses and workers. His campaign struggled to shake the perception, which was antithetical to Conservative political ideology, that he presided over a large state intervention during the coronavirus pandemic. It was intended to avert mass unemployment and economic depression.

Political experts believe Britain’s new leader is unlikely to make significant changes to the country’s foreign policy that would jeopardize its close relationship with the United States. However, one potential flashpoint that Truss inherits from Johnson is what to do with the border between Northern Ireland, which is part of the United Kingdom, and Ireland, which is part of the European Union, as a result of the United Kingdom’s exit from the European Union, known as Brexit.

This previously open border is now subject to checks on some goods and services, and Conservatives want to change customs and immigration rules, threatening the fragile peace that has existed in Northern Ireland since the US-brokered Good Friday Agreement went into effect in 1998.

Truss’s first priority will be to reassure the British public that she has a plan to deal with rapidly rising energy costs and an inflationary spiral caused by the lingering coronavirus pandemic, Russia’s unprovoked war in Ukraine, and Britain’s nearly two-year exit from the EU bloc. All three events disrupted supply chains and increased consumer costs.

The U.K. uses little Russian oil and gas, but according to Ofgem, Britain’s energy regulator, the average British household will pay around $4,200 per year to heat and power a home by next month. This represents an 80% annual increase and reflects how the British government has designed its energy market to be reliant on wholesale prices, which have skyrocketed due to the Ukraine conflict.

Forecasts indicate that energy bills in the United Kingdom could reach more than $7,700 early next year, which is more than many U.K. residents pay for rent or a mortgage, threatening to push millions into so-called fuel poverty and force many small businesses to close.

Queen Elizabeth will receive Johnson and Truss on Tuesday at Balmoral, her estate in Scotland, as part of the handover of power, according to Buckingham Palace.

It is a break from tradition. Normally the queen would host the departing and new British leaders at her London residence, which she has done 15 times before during her 70-year reign. In recent months the monarch, 96, has participated in fewer royal duties.