Boris Johnson, one of Britain’s most eccentric politicians, on track to be next prime minister

It’s an image burned into millions of British brains: Boris Johnson, then mayor of London, dangling haplessly from a zip line as he finds himself stranded in mid-zip, in midair.

He’s clad in a baggy business suit. A bit of floppy blond hair peeks from beneath an oversized-looking helmet. The harness holding him in place resembles a giant diaper — or nappy, as fellow Brits would say.

His toes point outward, Charlie Chaplin-style, as if he has just completed a particularly awkward pirouette. His trousers are hiked to reveal a slice of leg above the sock line. From each hand, he waves a British flag, which from a distance looks comically tiny.

Alexander Boris de Pfeffel Johnson looks entirely ridiculous. But improbably, he also looks perfectly at ease.

The 2012 photo is so well remembered, perhaps, because it seems to sum up so much about Johnson: the performative persona, the trademark outrageousness, the self-referential jokiness, an absolute immunity to embarrassment.

And beneath the flamboyance, there’s a flash of the unwavering ambition that is now nearly certain to culminate in Johnson taking up residence days from now at 10 Downing St., the storied residence of the prime minister of the United Kingdom.

A contest to elect the Conservative Party’s leader, who will become the country’s leader as well, is nearly complete. The voting by 160,000 party members — who skew white, wealthy and older — ended Sunday, with the winner expected to be announced Tuesday and installed in office as soon as Wednesday.

At 55, Johnson is a political figure who defies categorization — or, at times, seems to demand it. One of his biographers, Sonia Purnell, calls him a “Marmite politician,” after that peculiarly British foodstuff, a spreadable yeast extract that people tend to love or hate.

Either way, his improbable rise reflects a bizarre and confounding political moment for Britain as it barrels toward an Oct. 31 date for Brexit, its departure from the European Union.

Detractors call Johnson buffoonish and unprincipled, reckless and feckless. Admirers consider him refreshingly anti-establishment, bracingly unfiltered in his utterances, far smarter than he’s given credit for, with an Everyman appeal that belies his posh pedigree.

Gaffes and blunders that would sink most politicians seem to simply roll off Johnson. He’s prone to racist remarks such as calling nonwhite Commonwealth citizens “piccaninnies” — which he later said was satire. He also compared women in niqab, or face-covering veils with a slit for eyes, to mail slots.

While he was foreign secretary, he carelessly blurted out that Nazanin Zaghari-Ratcliffe, a British-Iranian woman arrested during a family visit to Iran, was teaching journalism while on her trip. That assertion, vehemently denied by her family and employer, is widely blamed for contributing to her continued imprisonment on spy charges.

More recently, Johnson drew scorn from some leading Conservatives when he appeared to almost casually capitulate to President Trump’s attacks against Britain’s widely respected envoy to Washington, Kim Darroch, after leaked diplomatic cables revealed the ambassador’s sometimes scathing take on the U.S. president’s personality and mode of governance. Darroch stepped down the day after Johnson, in a televised debate, failed to defend him.

While cultivating a colorful tabloid-friendly political style, the twice-divorced Johnson strenuously demands privacy in his personal life — although it occasionally bursts into messy public view, as it did earlier this summer when police were summoned after reports of a loud late-night domestic dispute between Johnson and his partner, Carrie Symonds.

Now that he is poised to become prime minister, there’s a jarring contrast between the air of antic hilarity that so often accrues to Johnson’s public image and the utter seriousness of Britain’s political predicament.

If he wins the race against his lone rival, Foreign Secretary Jeremy Hunt, he will take up the task that felled his predecessor, Theresa May: either leading the country as it splits from the EU without any deal — a scenario that economists warn could be economically disastrous — or managing to get some amended withdrawal agreement through Parliament.

Any further delays, or a softening of the government’s stance, would leave Johnson vulnerable to attacks by far-right figures such as Nigel Farage, leader of the hard-line Brexit Party that swept to victory in European Parliament elections two months ago.

Many believe Johnson is simply not up to the job.

“He’s lied his way through life; he’s lied his way through politics; he’s a huckster,” Conservative politician Chris Patten, who was the last British governor of Hong Kong, told Bloomberg TV this year. “As well as being mendacious, he’s incompetent.”

Britain voted to break away from the EU in 2016 after a bruising referendum campaign in which Johnson played a key role, cheerleading loudly for the “leavers.” His side won, but narrowly: 52% of voters backed the divorce, and 48% voted to remain in the bloc.

Street protests and legal challenges ensued, and politicians resigned, including then-Prime Minister David Cameron.

May, his successor, vowed to not only deliver Brexit by March 29, 2019, but to unite the country. But that deadline came and went, and she resigned in June after lawmakers three times decisively rejected the withdrawal agreement she struck with her EU counterparts.

EU officials agreed to the latest extension, but have repeatedly and categorically stated that the deal on offer is the only one available and not open to renegotiation.

That Johnson is poised to take up the leadership role at this extraordinarily delicate juncture is still mind-boggling to many of his compatriots. He himself has for years enjoyed delivering colorful variants on the improbability of his becoming prime minister.

“It is more likely that I will be reincarnated as an olive, locked in a disused fridge, decapitated by flying Frisbee,” he told Channel Four news in 2015.

But longtime observers say that hallmark flippancy masks relentless drive and determination. Biographer Andrew Gimson calls him “very, very ambitious.”

“He said he always wanted to be a member of Parliament, and always wanted to get to the top,” he said. “But he also wanted to do it on his own terms.”

Charisma has carried Johnson far, but he’s dogged by his reputation for unreliability.

“Boris, well — he’s the life and soul of the party, but he’s not the man you want driving you home at the end of the evening,” Conservative politician and then-Home Secretary Amber Rudd said in a 2016 debate before the Brexit referendum.

Others, pointing to Johnson’s long climb to the top, warned against dismissing outright his chances of success.

“I think he could be a good prime minister, but we simply can’t tell in advance,” said Gimson, adding that Johnson “might benefit from low expectations.”

One veteran of Britain’s rough-and-tumble politics, 86-year-old former Cabinet minister Michael Heseltine, said the likely new prime minister could be counted upon to do one thing, at least: to take a canny measure of public sentiment and act in the most opportunistic way possible.

Johnson is “a man who waits to see the way the crowd is running,” Heseltine said last year on the ITV program “Good Morning Britain.” And then, he said, he “dashes in front and says, ‘Follow me!’”

Special correspondent Boyle reported from London and Times staff writer King from Washington.