LONDON — Prime Minister Boris Johnson of Britain suffered a potentially lethal political blow on Tuesday when two of his most senior ministers quit in an apparently coordinated rebellion against his scandal-tainted leadership.
The two ministers — the chancellor of the Exchequer, Rishi Sunak, and the health secretary, Sajid Javid — submitted their resignations after Mr. Johnson apologized for the latest scandal to engulf his government, one that involves allegations of sexual misconduct and excessive drinking by a Conservative Party lawmaker.
The sudden departures opened another fissure in Mr. Johnson’s government at a time when he is already battling a mutiny among lawmakers in his party, who are angry after months of embarrassing reports of social gatherings at Downing Street that violated the government’s own coronavirus lockdown rules.
Mr. Johnson moved quickly to announce replacements for Mr. Sunak and Mr. Javid, signaling that he planned to try to steady the government and battle for his job. But by all accounts, the prime minister was in greater political peril than at any other time in his tumultuous three-year tenure in Downing Street.
Analysts and some senior Conservative lawmakers said the impact of the resignations could shatter whatever support Mr. Johnson had left in the party, and in the hours that followed, Alex Chalk, the solicitor general, and several holders of junior government posts also quit. Even analysts who have been reluctant to write the prime minister’s political obituary said he faced a forbidding path to avoid being toppled.
“I can’t see a way he gets through this — it really does look like the end of the road this time,” said Tim Bale, a professor of politics at Queen Mary University of London. “Javid and Sunak going together punches a far bigger hole in the cabinet than would have been the case had it just been one or the other.”
Mr. Johnson, a freewheeling journalist turned politician, has seemed to defy the laws of political gravity, surviving multiple investigations, a criminal fine by the police, and a no-confidence vote among lawmakers in his Conservative Party only last month — all related to the parties held in Downing Street during coronavirus lockdowns.
Because he survived the confidence vote, he cannot face another one for a year unless the party’s rules are changed. That means that cabinet resignations could be the only effective method of pressuring him to resign. High-profile resignations crippled some of Mr. Johnson’s predecessors, including Margaret Thatcher.
Part of Mr. Johnson’s strength had been the unified support of his cabinet, despite an unrelenting tide of negative headlines.
Hours after the resignations of Mr. Sunak and Mr. Javid, Mr. Johnson named Nadhim Zahawi, the education secretary who was better known for his energetic rollout of coronavirus vaccines, as chancellor of Exchequer, and Steve Barclay, his Downing Street chief of staff, as health secretary.
But the on-the-fly reshuffling raises its own problems. Mr. Barclay had only been recruited in February to clean up Downing Street after the parties scandal. Mr. Johnson also has yet to replace Oliver Dowden, a Conservative Party chairman who resigned after two damaging Parliamentary election defeats last month.
Those losses crystallized fears among many Conservatives that Mr. Johnson had lost his touch as a champion vote-getter, a reputation he cemented in the party’s landslide victory in 2019 and that had helped him weather all manner of scandals.
Still, it was the more recent outcry over Mr. Johnson’s promotion of a Conservative lawmaker, Chris Pincher, that appeared to tip Mr. Sunak and Mr. Javid.
Last week, Mr. Pincher resigned as the party’s deputy chief whip after admitting having been drunk at a private members’ club in London where, it was alleged, he groped two men. He was suspended from the party while the accusations were being investigated, but he has not resigned as a member of Parliament.
On Tuesday, Downing Street admitted that Mr. Johnson had been told about previous accusations against Mr. Pincher in 2019 — something Mr. Johnson’s office initially denied. In what has become a familiar ritual in British politics, the prime minister delivered a apology on the BBC for elevating Mr. Pincher.
“With hindsight it is the wrong thing to do,” Mr. Johnson said, “and I apologize to everyone who has been badly affected by it.”
If the prime minister calculated that the act of contrition would be enough to keep restive ministers and lawmakers in line, he was wrong. Mr. Sunak, who as chancellor occupied a post traditionally viewed as the second-most powerful in the government, submitted a bluntly critical letter of resignation.
“The public rightly expect government to be conducted properly, competently and seriously,” Mr. Sunak wrote. “I recognize this may be my last ministerial job, but I believe these standards are worth fighting for, and that is why I am resigning.”
Mr. Javid, who had preceded Mr. Sunak as chancellor before being forced out, and was then appointed by Mr. Johnson as health secretary, wrote: “It is with enormous regret that I must tell you I can no longer, in good conscience, continue to serve in this government. I am instinctively a team player but the British people also rightly expect integrity from their government.”
Both men are major figures in the party, with their own potential leadership aspirations, though Mr. Sunak’s star dimmed in recent months because of questions about his wealthy wife’s tax status in Britain.
One reason the cabinet’s support is important for Mr. Johnson is that it has prevented a major figure from emerging as a rival to him. Whether Mr. Sunak or Mr. Javid will try to take on that role is an open question — as is the question of whether other ambitious cabinet ministers will follow them out the door.
On Tuesday evening, it appeared that several high-profile cabinet ministers were staying on, including the foreign secretary, Liz Truss; the defense secretary, Ben Wallace; and Michael Gove, an erstwhile rival of Mr. Johnson who holds a key cabinet portfolio overseeing the economic policy of “leveling up” struggling areas.
Mr. Johnson successfully fended off the no-confidence vote in large part because there were no obvious successors to him, but it made his vulnerability starkly clear: more than 40 percent of his party’s lawmakers voted to oust him. An unraveling cabinet immediately puts several potential successors onstage. And party officials are already debating whether to change the rules to call another confidence vote earlier than next June.
The outcry over the circumstances of Mr. Pincher’s appointment — and Downing Street’s shifting account of them — is just the latest in a series of scandals surrounding Mr. Johnson. Earlier this year, he was fined by the police for breaking lockdown rules at Downing Street, where members of his staff were found to have held several boozy parties in violation of the pandemic prohibition.
Questions were also raised about Mr. Johnson’s costly refurbishment of his apartment in Downing Street, which was initially financed by a Conservative Party donor. The prime minister also staunchly defended a Conservative lawmaker, Owen Paterson, for violating lobbying rules, only to reverse course later and apologize.
As the latest drama unfolded on Tuesday evening, some Conservative lawmakers made clear they believed there should be no coming back for Mr. Johnson.
“I voted against Boris Johnson in the recent confidence vote, and earlier today reiterated my concerns,” Laurence Robertson, a veteran Conservative lawmaker, wrote in a post on Twitter. “Resignations of cabinet ministers show others agree the issues over the past months have become a distraction from the challenges facing the country. The PM must now resign.”
Mark Harper, a former chief whip, in his own post on Twitter, also discussed Mr. Sunak’s and Mr. Javid’s resignations. “Honorable decisions made by honorable men,” he said. “The Conservative Party still has so much to offer to our country. It’s time for a fresh start.”
Julian Knight, another Conservative member of Parliament wrote in a post on Twitter that with politicians like Mr. Javid and Mr. Sunak “saying enough is enough, then I’m afraid the die is cast. It is time for the party to take a new direction.”
Megan Specia contributed reporting.