Behind a heavy oak door in Parliament, Prime Minister Boris Johnson implored Conservative lawmakers to back him by voting for new restrictions to help slow the fast-spreading omicron variant.

The lawmakers cheered Johnson — yet almost 100 defied him, voting in the House of Commons against requiring vaccine passports for nightclubs and other crowded venues. The rebellion didn’t defeat the measure, which was approved with opposition support and took effect Wednesday. But it could have big implications for Johnson’s political future and for Britain’s pandemic response.

“It was a very clear message that colleagues are not happy with how the government is operating at the moment,” Mark Harper, one of the rebels, told Times Radio. “The team captain should be able to depend on the loyalty of the team, but it’s a two-way street.”

Tuesday’s rebellion by 98 Conservative lawmakers on vaccine certificates was by far the biggest of Johnson’s premiership, and an echo of the serial revolts that ousted his predecessor, Theresa May. More than 60 Tory legislators also voted against mandating vaccinations for all health care workers.

Johnson’s government argues that the restrictions are needed to confront the “grave threat” from the highly transmissible omicron variant, which is spreading so quickly it could overwhelm Britain’s hospitals even if it is less severe than previous strains.

Some on the party’s right wing don’t believe the dire warnings, and don’t like the “nanny state” measures the pandemic has brought. In Tuesday’s vote, they were joined by others wanting to send a warning to a prime minister whose approval ratings have plummeted amid policy U-turns and ethics scandals.

Any further coronavirus restrictions look certain to face strong resistance from Conservatives, leaving Johnson reliant on the opposition to get them approved.

“The prime minister is so weak that without Labour votes last night, vital public health measures wouldn’t have got through,” Labour Party leader Keir Starmer said Wednesday during Prime Minister’s Questions in the House of Commons.

“His MPs are wrong to vote against basic health measures, but they are not wrong to distrust him,” Starmer added.

The Conservatives chose Johnson as their leader in 2019 because the blustering, Latin-spouting former London mayor was anything but a typical politician. He’d been fired from a party job for lying, used racist and offensive language in columns and quips — but he was upbeat, entertaining and a hit with voters.

Johnson promised to “get Brexit done” after three years of gridlock over Britain’s departure from the European Union. He won a big victory in the December 2019 election by winning over voters in England’s “red wall,” a belt of former industrial towns that had long been Labour strongholds.

The pandemic knocked Johnson off course. His initial reluctance to impose a nationwide lockdown in early 2020 helped give the U.K. the highest coronavirus death toll in Europe apart from Russia, with more than 146,000 deaths.

A successful vaccination program helped Johnson recover some of his authority, but a slew of damaging allegations has tarnished him.

First there was an expensive refurbishment of the prime minister’s official Downing Street apartment, funded by a Conservative donor. Johnson was cleared of wrongdoing over the “cash for curtains” affair, but the party was fined by Britain’s political regulator.

Then the government faced charges of cronyism when it tried to block the suspension of Owen Paterson, a Conservative lawmaker found to have broken lobbying rules.

Most damaging are allegations that staff in Johnson’s office flouted coronavirus rules with lockdown-breaching Christmas parties last year, when others were banned from gathering. Johnson has ordered an inquiry, but insists he personally broke no rules.

It all adds up to a dangerous moment for Johnson.

Starmer is working to restore Labour’s fortunes after the party suffered four consecutive election defeats, and it has recently opened up a lead in opinion polls.

Danny Finkelstein, a Conservative member of the House of Lords, said Conservative lawmakers’ “large-scale open rebellion against government policy on the most important question of the day” amounted to a vote of no-confidence in the government.

“How long can such a position endure?” he asked in the Times of London.

A special election on Thursday for the North Shropshire parliamentary seat, formerly held by lobbying-scandal lawmaker Paterson, could add to Conservative jitters. Polls suggest the opposition Liberal Democrats have a chance of winning what has long been a staunchly Conservative district.

Britain is not scheduled to hold a national election until 2024, so Johnson may have time to recover. His popularity could rise if the omicron wave washing over the U.K. is not as bad as many fear, and Johnson meets his goal of offering all adults a booster vaccine by New Year’s Eve.

But the Conservatives have a long history of dumping leaders they consider liabilities. Several ministers — notably Treasury chief Rishi Sunak and Foreign Secretary Liz Truss — are already being discussed as possible replacements.

Jill Rutter, a senior fellow at the Institute for Government think-tank, said Johnson “looks much weakened, but it’s not clear to me if he is fatally weakened.”

“He still has some quite biggish advantages, particularly if you’re a red wall Conservative looking at who can get people to turn out for the Conservatives again,” she said. “Is Liz Truss, is Rishi Sunak, really going to bring them flocking to the ballot boxes in the way that Johnson’s star quality does? That’s not so clear.”

(AP)