Boris Johnson is the Harry Houdini of British politics, blustering his way through scandals about fibs, finances and a colorful love life that would have sunk most other British politicians.

On Wednesday, he embarked upon his most dangerous feat of escapology yet. The prime minister is accused of whooping it up in a garden party at his No. 10 Downing St. office while the rest of the country was locked down for the common good to halt the COVID-19 pandemic.

¡°Is this for real?¡± replied one Downing Street staff member to a party invitation from Johnson¡¯s private secretary Martin Reynolds during the first and strictest U.K. lockdown. But the invitation wasn¡¯t a spoof. Up to 100 ¡°guests¡± were asked to ¡°bring your own booze¡± to the No. 10 garden on May 20, 2020.

Most of those invited had the good sense to stay away, but more than 30 others turned up, bottles to hand. Johnson by his own admission attended for 25 minutes. He¡¯d thought it was a work event, he explained to an incredulous House of Commons on Wednesday, adding that he had only taken a turn around the garden to thank his hard-working officials.

This week Johnson should have been celebrating the success of his gamble to keep the country open during the outbreak of the omicron variant. Cases have halved, the booster vaccine roll-out has been a success and remaining social restrictions are set to be lifted before the end of the month, ahead of continental Europe.

Instead, the prime minister is fighting for his political life ¡ª and he has no one to blame for his predicament but himself.

The rules were clear. Indeed, a Cabinet minister had outlined them to the nation¡¯s media an hour before the party started: Individuals were allowed to meet just one person from outside their household in the open air. Ten days before, Johnson had also urged people on television, with a Union flag in the background, to ¡°observe the rules.¡± Elsewhere in England, millions observed the grim rituals of lockdown, isolating at home and forgoing visits to parents, sick relatives and other loved ones. Funerals and marriages were restricted to six people.

Everyone hates a leader who operates according to, ¡°Do as I say, not as I do.¡± The charge that COVID-19 social distancing rules only apply to the little people has already proved terminal to several members of Johnson¡¯s government.

The last Health Secretary was forced to resign when he was caught on camera in a clinch with a political adviser who wasn¡¯t his wife. Johnson¡¯s media spokeswoman had to resign, too, because she was filmed laughing about No. 10 ¡°parties¡± recently. The prime minister¡¯s...