Opinion | Donald Trump Too Tame for You? Meet Britain’s Boris Johnson

The front-runner to become Britain’s next prime minister is a portly white man with unkempt blond hair, an adoring base of supporters, disdain for Europe, a dodgy private life and a loose relationship with truth and principle. There are also differences between Boris Johnson and Donald Trump, but the similarities have been much noted in some European circles, with no small misgivings.

The biggest difference is that Mr. Johnson, who is 55, has been around politics all his life, as a journalist, member of Parliament, mayor of London and foreign secretary. His forte has not been conservative conviction, major achievement or great vision, but one of the sharpest tongues in British politics.

Like Mr. Trump with his tweets and rants, Mr. Johnson delights his followers with outrageous statements that they take as straight talk — even when he has gone so far as to describe Africans as “piccaninnies” or to ascribe President Barack Obama’s opposition to Brexit to an “ancestral dislike” of Britain as the son of a Kenyan.

His most commonly quoted quip these days is the one summing up his position on Brexit as having one’s cake and eating it. Curiously, Mr. Johnson was initially unsure of his position on leaving or remaining in the European Union — an unpublished article he wrote days before he came out in favor of leaving made a strong argument in favor of staying. Mr. Johnson says he was simply sorting out his thoughts.

Once he did that, Mr. Johnson swiftly became a premier campaigner for “Vote Leave,” touring Britain in a double-decker bus emblazoned with the claim that Britain pays 350 million pounds a week into the E.U.’s collective budget. That the claim was false did not trouble Mr. Johnson. He was fired from an early job in journalism for making up a quote, and one of his journalism colleagues once wrote of him, “Boris told such dreadful lies / It made one gasp and stretch one’s eyes.”

All that has made for great political theater and has positioned Mr. Johnson as likely to defeat Foreign Secretary Jeremy Hunt when the roughly 160,000 Conservative Party members — 70 percent men, 97 percent white, average age 57 — vote for their new leader, who then becomes prime minister because the Conservatives control the largest number of seats in Parliament. The winner will be announced on July 23, shortly before Parliament goes into recess.

Mr. Johnson could still founder — his standing dropped after a well-publicized recent altercation with his partner, Carrie Symonds, that prompted neighbors to call the police. But the more likely scenario is that Mr. Johnson will become prime minister with three months left before the current Oct. 31 deadline to reach a separation agreement with the European Union and avoid a chaotic no-deal Brexit.

And so, once again, a question mark hovers over Britain. Campaigning for Conservative votes, which are largely pro-Brexit, Mr. Johnson has spoken of renegotiating Prime Minister Theresa May’s withdrawal agreement, which Parliament rejected three times, while pledging that no matter what, Britain will leave the E.U. on Oct. 31. “Being ready to do so,” he wrote in an open letter to Mr. Hunt on Tuesday, challenging his rival to take the same position, “is the best way to convince our European friends that we are serious in these negotiations and to get a better deal.”

It strains credulity that the European Union would reopen the agreement or that any wholly new set of terms for leaving the union would pass Parliament — or that the E.U. would show any sympathy and patience for Mr. Johnson, whom the French newspaper Le Monde called a “small-scale Trump.” Whether Mr. Hunt, who has campaigned as the responsible adult, could do better is another open question.

The answer will not be long in coming. But if the chaotic history of Britain’s Brexit debate is any guide, whatever it is will only bring on the next vexing questions.