A plate-hurling, screaming quarrel with his latest girlfriend has turned the spotlight fully on where Boris Johnson's advisers didn't want it - on his character and chaotic private life, which even his friends have described as "unruly."
The altercation, recorded by neighbors in south London who phoned the police, has thrown a wrench into Johnson's smooth-running campaign to succeed Theresa May as Britain's prime minister, which commentators say is his race to lose.
His bid to win a leadership contest, which is now in its final stages after lawmakers whittled down in knockout ballots the succession choice to two candidates for the party's 160,000 members to vote on by mail, has been built on avoiding television debates and dodging journalists.
Johnson has refused to answer questions about the screaming match in the apartment of his girlfriend, 31-year-old Carrie Symonds, but calls are mounting on the 55-year-old to address questions about the altercation on Friday.
Johnson ended a 25-year-long marriage, his second divorce, to move in last year with the younger Symonds, but his unruly private life has been marked by serial relationships, children fathered out of wedlock and terminated pregnancies.
The quarrel has allowed his remaining opponent in the leadership race, the country's current and normally mild-mannered foreign minister, Jeremy Hunt, to pile on the pressure and to launch Monday an uncharacteristically personal attack on his rival, accusing him of being a "coward" by trying to avoid public scrutiny and "slink through the back door" of Downing Street.
Johnson, who was finally backed by more than half of Conservative lawmakers to be the new party leader has appeared on only one TV debate and granted a single short broadcast interview and one newspaper interview. Hunt says the public want a "fair and open contest, not one that one side is trying to rig to avoid scrutiny."
He added: "One of the strengths of our system is that we scrutinize our politicians with more intelligent ferocity than anywhere else in the World. But in this case it just isn't happening. Nothing could be worse for a new prime minister in these challenging times than to come to power with a fake contest."
Hunt's aides say it is especially important for May's successor to be scrutinized closely as they will be entering Downing Street not via a general election but through a party vote with their democratic legitimacy questioned because the country as a whole would not have had any say in their selection.
Hunt says he doesn't want to quiz Johnson, a former two-term London mayor and short-lived foreign minister, about his private life, but about his claim that he can "guarantee" Britain will leave the European Union by October 31, the latest deadline for the country's exit from the bloc.
But while Hunt is avoiding focusing directly on Johnson's character, some of his aides are happily fanning the flames and briefing reporters behind the scenes that the frontrunner's highly colorful private life represents a security risk. It could leave him vulnerable to leaks about past behavior and even open to blackmail by foreign powers, they charge.
The accusation has infuriated Johnson supporters, who say the explosive argument between Symonds and Johnson was just a normal domestic "tiff" apparently provoked by Johnson spilling red wine on a sofa. They maintain the quarrel was blown out of proportion by neighbors who are politically motivated. The police left without charging anyone.
Nonetheless, the dispute, which is depressing Johnson's poll numbers, is contributing to a picture of a Conservative party in disarray and fearful that it is facing an existential crisis because of Brexit. It comes as pro-European Union Conservatives have started to plot a strategy to wreck a Johnson-led government, if he seeks to take Britain out of the European bloc without an exit deal approved by Brussels.
Sharp divisions between Brexiters and pro-EU lawmakers wrecked Theresa May's prime ministership and there are growing signs that it might quickly upend Johnson's, too, if he wins the leadership race.
May's fate was sealed when the British House of Commons declined three times to approve a Brexit Withdrawal Agreement she negotiated with Brussels - a deal vehemently opposed by a third of her own parliamentary party on the grounds it would keep Britain subservient to EU regulations and rules and prevent it from negotiating trade deals bilaterally with non-EU countries.
Europhiles are also opposed to the deal. Several top Conservatives who want to retain close ties with the EU have warned they could join opposition parties in a non-confidence vote in the House of Commons and bring down a Johnson government.
A former Conservative attorney-general, Dominic Grieve, said: "If the new prime minister announces that he is taking the country on a magical mystery tour towards an October 31 crash-out, I don't think that prime minister is going to survive very long."
Even Britain's current top finance minister, Philip Hammond, has warned the next prime minister "will not survive," if they seek to leave the EU without a deal. He has declined publicly to rule out that he would vote with opposition parties against Johnson, if he sought a no-deal Brexit.
Britain's fractious Conservatives are ruling as a minority government, and they rely on the support of a Northern Irish party to give them a working majority of just three in the House of Commons. A handful of Conservative standouts could trigger a chain of events leading to an early election the Conservatives are unlikely to win.
Johnson's supporters say he remains the favorite of party activists because he has the star quality the party needs to win elections and curb both the populist threat from Nigel Farage's new Brexit party and combat Labour's Jeremy Corbyn.
They also claim he has the political inventiveness to break the Brexit deadlock that has turned traditional British politics upside down and might even have the ability to persuade hardline Brexiters to accept a compromise and something short of their objective to break completely with the EU.