Before his spectacular falling-out with Boris Johnson, Rishi Sunak was on a rapid rise that could still end with him installed as Britain's first prime minister of colour.

It would be a historic landmark, if the Hindu descendant of immigrants from Britain's old empire in India and East Africa were to take command of the world's fifth largest economy.

But after making the final run-off following a series of votes by Conservative MPs, Sunak must first persuade the party's members as ballot papers go out on Monday -- and he is well behind Liz Truss.

Opinion polls show that she has so far outflanked him with policies geared to the Tory right, which also mistrusts Sunak's role in a cabinet revolt that unseated Johnson after months of scandal.

Fabulously rich from his pre-politics career in finance, the former chancellor of the exchequer has also been mocked as being out of touch when Britons are contending with surging inflation.

On the campaign trail this month, he wore expensive Prada loafers on a visit to a building site, and was accused of "mansplaining" to Truss during a bad-tempered TV debate when he savaged her tax-cutting plans.

Instead, Sunak argues, Britain needs a Thatcherite dose of "sound money" to quell inflation and get growth back on track.

Video footage also emerged of a 21-year-old Sunak describing his mix of friends following his education at Winchester College, one of Britain's most exclusive private schools, and the University of Oxford.

"I have friends who are aristocrats, I have friends who are upper class, I have friends who are, you know, working class," he said, before adding: "Well, not working class."

Dishy Rishi

A details-oriented policy wonk, Sunak, 42, was an early backer of Brexit, and took over as chancellor in February 2020.

It was a baptism of fire for the Tory rising star, as the Covid pandemic erupted.

He was forced to craft an enormous economic support package at breakneck speed, which he now says needs to be paid off.

In India, Sunak has been better known through his wife Akshata Murty. She is the daughter of Indian tycoon Narayana Murthy, the billionaire co-founder of information-technology group Infosys.

The Sunaks met while studying in California and they have two young daughters -- along with a photogenic dog.

The ex-minister's Instagram-friendly profile earned him the media nickname of "Dishy Rishi".

Partygate fine

Until last year, Sunak held a US Green Card -- which critics said suggested a lack of long-term loyalty to Britain.

And he has faced difficult questions over Murty's failure until recently to pay UK taxes on her Infosys returns, which opinion polls suggest was viewed with deep disfavour by voters.

Sunak has already been marked by the scandals of Johnson's tumultuous premiership.

In November 2020, he marked the Hindu festival of Diwali by lighting oil lamps on the front step of the chancellor's official residence at 11 Downing Street -- while urging other Hindus to stick to England's Covid lockdown.

Johnson was less observant of the rules, drawing a police fine for one lockdown breach as part of an investigation into the "Partygate" affair.

But Sunak also ended up with a police fine, after joining a birthday gathering for Johnson when he arrived early for a Downing Street meeting.

Along with the controversy over his family fortune, the Partygate scandal sullied the reputation of the teetotal Sunak, who admits only to a fondness for Coca-Cola and sugary confectioneries.

Waiter to wealth

Sunak represents the constituency of Richmond in Yorkshire, northern England -- a safe Conservative seat he took over in 2015 from former party leader and foreign secretary William Hague, who described him as "exceptional".

Sunak swears his oath of allegiance as an MP on the Bhagavad Gita. Theresa May gave him his first job in government in January 2018, making him a junior minister for local government, parks and troubled families.

Sunak's grandparents were from Punjab in northern India and emigrated to Britain from eastern Africa in the 1960s.

They arrived with "very little", Sunak told MPs in his maiden speech in 2015.

His father was a family doctor in Southampton on the southern English coast, and his mother ran a local pharmacy.

Sunak waited tables in a local Indian restaurant, before progressing to Oxford and then Stanford University in California.

Sunak insists that both his own family's experience, and that of his mega-rich wife's, are a "very Conservative" story of hard work and aspiration. He will soon learn if the party members agree.