LONDON — In recent weeks Prime Minister Boris Johnson of Britain has revived his fortunes at home by becoming Europe’s most aggressive supporter of Ukraine’s fierce fight against Russian invasion.
But on Tuesday Mr. Johnson was battling for his own survival again, after police fined him for attending a lockdown party in Downing Street that broke coronavirus laws made in the very same building.
Mr. Johnson said on Tuesday night that he had paid the fine, though he did not say how much it was, insisting that he would continue in his job despite calls for his resignation, including from the opposition Labour leader. He added: “I once again offer a full apology.”
The announcement earlier Tuesday by London’s Metropolitan Police made Mr. Johnson the first holder of his office in living memory to be found in breach of the law, and provoked anger from Britons who obeyed strict coronavirus rules that sometimes even forbade contact with dying relatives.
It also prompted opposition politicians to accuse Mr. Johnson of lying to Parliament by denying that breaches of coronavirus rules occurred in Downing Street or other government buildings. That is dangerous territory for Mr. Johnson because, in Britain, ministers are normally expected to resign if they mislead their fellow lawmakers.
But the announcement came after several weeks in which Mr. Johnson has stabilized his leadership through robust support for Ukraine’s resistance against Russian military aggression, culminating in his surprise weekend visit to Kyiv, the Ukrainian capital.
The media’s focus on the war has defused the air of crisis around Downing Street and prompted several internal critics who had made formal demands for a vote of no-confidence in Mr. Johnson, to retract them.
One of those, Douglas Ross, the leader of the Scottish Conservatives, said on Tuesday that, with conflict raging in Ukraine, “it wouldn’t be right to remove the prime minister at this time.”
Nonetheless the latest twist in the “partygate” saga is an extraordinary development even for Mr. Johnson who has a reputation for extracting himself from crises of his own making.
In a statement, London’s Metropolitan Police said it would issue fines for at least 50 breaches of the law as part of its inquiry into the “partygate” scandal that, earlier this year, threatened to sweep Mr. Johnson from power after reports emerged of politicians and officials gathering and drinking in Downing Street and other government buildings despite coronavirus rules.
The police did not name any of those to be fined, but the prime minister’s office later said that Mr. Johnson and the chancellor of the Exchequer, Rishi Sunak, had both been notified that they had broken the law.
Mr. Sunak said Tuesday night that he had also paid his fine and apologized.
Mr. Johnson’s fine was for attending a party on his birthday on June 19, 2020, in the Cabinet Room at 10 Downing Street between 2 and 3 p.m., said a later statement from his office. His wife, Carrie Johnson, has also been told that she will be fined, her spokesperson said in a statement.
On Tuesday the leader of the opposition Labour Party, Keir Starmer, was among those demanding Mr. Johnson’s resignation and critics have asked for Parliament, which is on Easter recess, to be recalled.
More important, however, was the muted reaction of lawmakers in the governing Conservative Party, the only group that could force a no-confidence motion for Mr. Johnson. Fifty-four of them would have to demand one.
Because lawmakers are on recess this week, it will be harder for Mr. Johnson’s internal critics to organize against him. Some of Mr. Johnson’s allies have argued in the past that receiving a fixed penalty notice is more akin to a speeding ticket than a successful prosecution and a group of loyal lawmakers have rallied around the prime minister in recent months.
In January, Conor Burns, a lawmaker and supporter of Mr. Johnson, dismissed reports of the birthday gathering for which Mr. Johnson was penalized on Tuesday as trivial. “He was, in a sense, ambushed with a cake,” Mr. Burns said, provoking much ridicule.
The prime minister’s position inside the Conservative Party has also been strengthened in recent days because of a crisis engulfing Mr. Sunak, the man many assumed to be in prime position to take over were Mr. Johnson to fall.
The situation remains precarious for Mr. Johnson. He is now in the uncomfortable position of being a prime minister known to have broken laws that he made himself and the scandal has been particularly damaging because, at the time of the Downing Street parties, Britons were facing extreme curbs on their liberties to contain the spread of the coronavirus.
“Boris Johnson was partying and breaking his own lockdown rules, while we were unable to be at loved ones’ sides in their dying moments, or in miserable funerals with only a handful of people,” said a statement on Twitter from a group called Covid-19 Bereaved Families for Justice U.K.
Understand Boris Johnson’s Recent Troubles
Turmoil at Downing Street. A steady drip of disclosures about parties that violated lockdown rules has ensnared Prime Minister Boris Johnson of Britain in a scandal that could threaten his hold on power. Here is what to know:
“There is simply no way either the prime minister or chancellor can continue. Their dishonesty has caused untold hurt to the bereaved,” it added.
The Metropolitan Police’s inquiry into the parties is still underway and its statement on Tuesday said that officers were “continuing to assess significant amounts of investigative material” — a hint, perhaps, that further fines are to come. Mr. Johnson is known to have attended at least one other event under investigation.
Even after being judged to have broken the rules, Mr. Johnson faces further embarrassment because he has promised that, once the police investigation is complete, he will publish an internal government report into Downing Street parties. An interim version of that document, compiled by the senior civil servant Sue Gray, was damaging enough to precipitate the police investigation.
Against this backdrop, Conservatives face a test of their popularity next month in local elections, and a poor result would further increase pressure on Mr. Johnson.
But before that Mr. Johnson is certain to face an angry reception from opposition politicians when Parliament returns next week, with some claiming that the code under which ministers serve requires his resignation for misleading them.
The prime minister had “knowingly lied” to Parliament and to the public when denying that lockdown-breaking parties had taken place, wrote Caroline Lucas, a lawmaker for the Greens, on Twitter. Under the ministerial code, ministers have a duty to uphold the law, she said, adding: “If he’s allowed to stay on, it would be a constitutional crisis.”
And, though Mr. Johnson’s position has undoubtedly been strengthened by his handling of the crisis in Ukraine, as a biographer of Winston Churchill, he will know that Britain has replaced its prime ministers before in times of conflict, including during World War II.
Megan Specia contributed reporting.