UK Foreign Secretary Liz Truss becomes the third woman to take the helm in Downing Street after running a more successful campaign to become the new prime minister than rival Rishi Sunak.
The victory — scooping up 81,326 votes from party members ahead of Mr Sunak's 60,399 — follows in the footsteps of Margaret Thatcher and Theresa May.
Ms Truss, 47, became a strong contender to replace Boris Johnson early in the race, thanks to her public image as a Brexit-supporting libertarian who opposes high taxes and wasteful spending.
Who is Liz Truss?
Born in Yorkshire to a maths professor father and a teacher mother, Ms Truss came from a Labour-leaning family.
During her younger years, she joined her parents on anti-Thatcher demonstrations and as a teenager progressed to the Liberal Democrats' youth and student wing, frequently taking part in protests.
The politically minded Ms Truss became president of the Lib Dems while studying at the University of Oxford, but switched to the Conservatives after graduation.
She spent more than a decade in the private sector, primarily as a management accountant and then as deputy director at the right-of-centre think tank Reform.
She is married to accountant Hugh O'Leary and the couple have two daughters, Frances and Liberty.
Ms Truss spent two years as a Conservative councillor for Greenwich borough in south-east London before being elected as MP for South-West Norfolk in 2010.
She lives with her husband and children in a three-bedroom detached home in the market town of Thetford in her constituency. She frequently stays at her second home in Greenwich.
From Remainer to Brexiteer
Ms Truss voted “remain” in the 2016 Brexit referendum, only to later advocate the UK leaving the EU.
Promoting her bid to become prime minister, Ms Truss took to Twitter to say she had a “clear vision” for Britain and possessed “the experience and resolve to deliver it”.
Her zeal for limited government resulted in her pledge during the early stages of her campaign to “start cutting taxes from day one” and reverse a planned National Insurance increase.
That stance played well with the Conservative base but raised eyebrows among others, who fear such promises will make the party appear naive when it comes to fiscal matters.
She has served under three prime ministers — David Cameron, Mrs May and Mr Johnson. The latter found a staunch ally in Ms Truss and in September 2021 rewarded her for her loyalty with a promotion from international trade secretary to foreign secretary.
New PM's tough stance on Russia
Since being appointed to head the Foreign, Commonwealth and Development Office, Ms Truss's outspoken stance against Russian President Vladimir Putin's invasion of Ukraine has been seen as an example of her no-nonsense approach to challenging issues on the international stage.
A few weeks before Mr Putin ordered his troops to cross the borders into Ukraine, Ms Truss arrived in Moscow for crisis talks with her Russian counterpart Sergey Lavrov.
Before the high-stakes summit, she posted a bold tweet demanding Russia withdraw more than 100,000 troops from the boundaries with Ukraine “or face severe consequences”, and said an incursion would be “a huge mistake”.
Her combative nature and striking warning about the possibility of a conflict between Russia and the West after the February 24 invasion of Ukraine landed her in hot water.
Kremlin spokesman Dmitry Peskov condemned what he called “absolutely unacceptable” remarks about possible “clashes” between Nato and Moscow.
He said comments by Ms Truss and others had fuelled Moscow's decision to put its nuclear arsenal on a “special regime of combat duty”.
Channelling Margaret Thatcher
Echoing her political idol Ms Thatcher, Ms Truss has stressed the need to support democracies and said the West must “face down global aggressors” such as China and Russia.
She has, time and again, been compared to Ms Thatcher. She has been accused of attempting to emulate her with staged photo opportunities by posing alongside a calf, riding in a military tank and donning a similar fur hat during a diplomatic trip to Moscow.
Business Secretary Kwasi Kwarteng was among the first Tory MPs to publicly back Ms Truss's bid for No 10. Tipped to become chancellor of the exchequer in her cabinet, he said her libertarian stance was one of the reasons he decided to support her.
“Liz’s basic instinct on tax is right … She doesn’t think people should be paying increasingly higher taxes to pay for higher spending”, Mr Kwarteng said.
Culture Secretary Nadine Dorries and Brexit Opportunities Minister Jacob Rees-Mogg also backed Ms Truss's campaign, cementing her position as the arch-Brexiteers' candidate of choice.
In the past, she has put forward her Brexit credentials, looking ahead to a “confident, outward-looking, patriotic and positive” future for the UK.