Now he has to weigh up whether he can convince Britain's governing party he is the man to save it from chaos.

The former finance minister was runner-up in the last contest to become Britain's prime minister which only concluded six weeks ago, despite being the most popular candidate amongst Conservative lawmakers in parliament.

But he was beaten by Liz Truss in the deciding vote by grassroots party members, with many blaming him for the downfall of their hero Boris Johnson.

It was Sunak's dramatic decision to quit in July which set off a wave of resignations by ministers, ultimately forcing Johnson to reluctantly give up the top job in Downing Street.

During the summer's leadership contest Sunak warned that Truss's tax cuts would cause a jump in borrowing costs, a message that proved to be correct as her economic programme triggered a bond market rout that led to her demise.

Sunak, 42, had warned that her plans to fund the proposals through extra borrowing were reckless and could worsen decades-high inflation as well as market confidence in the UK.

Now that he has been proved right, Sunak was installed by bookmakers as the early favourite following Truss's dramatic announcement.

He garnered the support of the largest number of Tory lawmakers in successive rounds of voting, before party members installed Truss.

A new YouGov poll on Tuesday found he has the best ratings of the touted alternatives to Truss -- albeit still with an overall net favourability rating of -18.

But he is also now viewed as a divisive figure.

Many party members, who usually get the final say on who leads the party, are unwilling to forgive him for his role in ousting ex-prime minister Boris Johnson.

With the Conservatives in turmoil, many in his party think he is the only one who can solve the party's woes.

"He has the plan & credibility to restore financial stability, help get inflation down & deliver sustainable tax cuts over time; and unite the Conservatives by bringing the best talent into govt to deliver for the British people," former Deputy Prime Minister Dominic Raab said, quoted by AFP.

For his supporters in the party, Sunak's previous leadership campaign message of the need for economic prudence to address Britain's rampant inflation and criticism of Truss's "fairy tale" plans have shown he is right man for the job.

But he will have to weigh up whether he can overcome hostility from those in the party members who remain aggrieved by his perceived treachery over Johnson, and for raising Britain's tax burden to its highest in decades, just as the country was heading into a severe cost-of-living squeeze.

Out of Touch?

Accusations that he was an out-of-touch former hedge fund boss were heightened in April when his wife - the daughter of an Indian billionaire - confirmed reports that she had non-domiciled tax status in Britain, something she agreed to end.

Betting firms have again made Sunak the front-runner to win the new contest although he was also the favourite in the race that Truss eventually won.

The problems for Sunak in the leadership race contrasted with his swift rise through the Conservative Party, which began in 2015 when he was elected to parliament having previously worked for Goldman Sachs and hedge fund TCI.

In 2020, aged 39, Sunak was named finance minister just before the coronavirus pandemic hit Britain. He dropped the Conservatives' small-state instincts to borrow massively and stave off the risk of an economic depression.

That made him one of the most popular politicians in the country, as he was praised for helping businesses and workers.

In one photograph that captured the sense of unity behind his rescue plans, Sunak posed outside his Downing Street office flanked by the heads of Britain's biggest trade union group and a leading employers' group.

But that consensus disappeared as Britain emerged from the crisis saddled with an extra 400 billion pounds of debt and then fell into a cost-of-living crisis that led to even more demands on the public purse.

Polls earlier this year showed his stock had fallen with the public, who were worried about the cost of living crisis and angered that he had raised payroll taxes while his wife had avoided British levies.