The irony shouldn’t be lost on Truss. In the 1980s, she spent part of her childhood in Scotland where her Labour-supporting parents were involved in anti-nuclear marches dominated by one particular political chant: “Maggie, Maggie, Maggie, oot, oot, oot.”

‘Well, I think my mum will, I’m not sure about my dad.’

Liz Truss on if her parents would vote for her

And as a teenager at Oxford, Truss used a speech as a then member of the university’s Liberal Democrats movement to argue the Queen be dumped and Britain become a republic, saying: “We … believe in opportunity for all. We do not believe people are born to rule.”

She told the BBC last year: “I think it’s fair to say that when I was in my youth I was a professional controversialist and I liked exploring ideas and stirring things up.”

“I came from a left-wing background. My mother was in the campaign for nuclear disarmament. There were very few people at my school or who I met on a regular basis in fact, I could count them on one hand, who you’d describe as right-wing.“

Ask recently if her parents would even vote for her in a general election, she replied: “Well, I think my mum will, I’m not sure about my dad.”

Truss, elected to parliament in 2010, has proven herself to be a great survivor throughout the premierships of Boris Johnson, Theresa May and David Cameron — having held several cabinet postings and showing herself to be an ambitious MP who earned her moment to strike for the leadership.

She has also proven herself to be a great gymnast. She was a staunch member of the Remain camp during the European Union referendum and has since been among the most vocal supporters of Brexit.

And it is her capacity to constantly change that has made her a formidable political opponent not only in the Conservative leadership race but potentially for Labour at the next general election.

“Changing your mind is often thought of as a weakness in politicians, whereas in reality, an unchanging commitment to ideology is one of their most eccentric habits,” John McTernan, a former adviser to both Tony Blair and Julia Gillard, observed recently. “In normal life, we change our minds frequently and without fuss.

“The fact Liz Truss has been on a political journey also makes her a powerful communicator. Some of the most persuasive arguments in politics are based on empathy rather than angry disagreement.

“Her speaking style is clear and simple. The listener readily understands what she thinks and believes. Her opponents who too readily dismiss her as simplistic are missing the point.”

McTernan, along with Peter Mandelson, an architect of Blair’s election victory in 1997, has been vocal in warning Labour not to take the mayhem within the Conservative government which had led to a fourth leader in seven years, for granted.

A graduate in philosophy, politics and economics, Truss juggled her professional career in London — first as an economist for Shell then as head of public affairs for Cable & Wireless — with her political ambitions. Having run unsuccessfully twice, she was a star candidate when Cameron would lead the Tories out of the political wilderness in 2010.

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But she had faced a fierce and embarrassing battle against de-selection by party members after the Daily Mail revealed before the campaign that some years earlier, she’d had an 18-month affair with a Tory MP, Mark Field, 10 years her senior. Both were married at the time of their liaison.

Truss door-knocked every party member – dubbed the “Turnip Taliban” — to explain herself and an effort to oust her failed. She went on to win the seat by more than 13,000 votes. She has fiercely guarded her privacy since, with her husband and two daughters rarely seen in public settings.

While her constant rebranding has made it difficult to label her politics, her close friend, former Australian high commissioner to London George Brandis, best described her as a “Thatcherite neo-liberal” who ultimately believes in freedom of choice and speech, and freedom from political correctness, big government and high taxes.

Over the past six weeks of campaigning, she had made several commitments to reform the tax system while promising to scrap April’s National Insurance rise – a British form of the Medicare levy – and to underwrite the cost of nuclear energy.

While playing to several bases within the ranks she has vowed to deliver net-zero carbon emissions by 2050 but remove green energy levies from energy bills and end the “anti-car rhetoric” of local councils.

She says Britain must now pay off COVID debt over a longer period to focus on cost-of-living issues and also wants to encourage workers back into offices. She has promised more Rwanda-style schemes to reduce illegal immigration but wants uncapped skilled migration to fill labour shortages.

Truss has vowed to continue Britain’s tough stance against Putin and China’s rising assertiveness in the Indo-Pacific, and will increase defence spending to 3 per cent of GDP by 2030.

While some of her political opponents fret over what her ascendancy means for their hopes, some of those who should be her allies are more than willing to mock her.

“She’s not a nasty person,” said former Tory MP, adviser to Thatcher and political commentator Matthew Parris. “Everybody I know who knows her, or has worked with her, likes her. She is a very likeable person. She’s just a bit crackers!”

Parris has described Truss as “intellectually shallow”, with “wafer-thin” convictions, and “a planet-sized mass of overconfidence and ambition teetering upon a pinhead of a political brain”.

“Any decision to follow Johnson with Truss to the doner kebab which, after a night on the tiles, momentarily seems like a good idea — until you open the bread pouch,” he wrote this week in The Times.

While Britain’s economy and cost-of-living crisis would occupy Truss’s immediate focus, she does carry some baggage from her time as Britain’s most senior diplomat.

Her relations with EU countries are clouded by the bitter row over how to trade across the Irish Sea after Brexit while keeping both the Northern Irish unionists and republicans happy. Her expected emergence on the world stage is also poorly timed, with potential conservative allies in the United States, Germany and Australia all ousted in elections over the past two years.

But Dan Tehan, the former trade minister in the Morrison government, said Australia had “true friend” and “like-minded traveller” in Truss, regardless of which party was in power.

The Victorian MP was exposed to one of those so-called “crackers” moments last year when Truss was international trade secretary and hoping to close a historic deal with Australia.

Tehan was leading a trade delegation as the newly appointed minister to London with the intent of finalising negotiations when it was reported that “allies” of Truss believed he was “inexperienced compared to Liz” and that Australia needed to “show us the colour of their money”.

London’s Telegraph had reported that Truss planned to “sit him down ... in an uncomfortable chair, so he has to deal with her directly for nine hours”.

“The story broke as I was boarding a plane in Paris, and by the time the short flight to London had landed, my phone had nearly melted from missed calls and incoming texts,” he said.

“One of the earliest missed calls was from Liz, who immediately apologised. Others will speculate about the source and intent of the news story but I viewed her apology as a sign of character.

“It meant I could tell the excited press that the issue had been resolved and we had put it behind us.”

He said Truss was a “professional and formidable opponent”, who “gave as good as she got”.

“I formed the view that she was rational; someone who was prepared to listen, and who wanted to understand the details of all the issues.

“She also wanted what was best for Britain. In our negotiations it was clear that she saw Brexit not merely as the cutting of ties with Europe but as an opportunity for Britain to forge its own, independent way forward.”