LONDON — His support crumbling, his government in disarray, his alibis exhausted, Prime Minister Boris Johnson of Britain tried frantically on Wednesday to salvage his position, even as a delegation of cabinet colleagues traveled to Downing Street to plead with their scandal-scarred leader to step down.
More than 30 government ministers or aides quit, multiple Conservative Party lawmakers urged Mr. Johnson to resign, and he got a withering reception in Parliament, where backbenchers jeered, “Bye, Boris!” as he left by a side door after a merciless grilling over his handling of the party’s latest sex-and-bullying scandal.
On a day of fast-moving developments, Mr. Johnson vowed to fight on, insisting he had a mandate from voters to steer Britain into its post-Brexit future, even as rebellious cabinet ministers try to dislodge him. But elsewhere in Westminster, lawmakers weighed — and then postponed, for a few days at least — a change in party rules that would allow another confidence vote, possibly next week, against the prime minister, who survived such a vote just a month ago.
There was a growing consensus that, however events play out over the next few hours or days, the curtain was falling on the era of Boris Johnson. Less than three years after he entered Downing Street, before riding a wave of pro-Brexit passion to win a landslide election victory, Mr. Johnson seemed cornered — a protean political gambler finally out of moves.
That does not mean the end will come quickly or gracefully. Mr. Johnson resisted the appeals of the cabinet delegation to resign. He has not ruled out calling a snap election to throw his fate to British voters. Such a move would need the assent of Queen Elizabeth II, which could precipitate a political crisis.
“The job of a prime minister in difficult circumstances, when he’s been handed a colossal mandate, is to keep going,” a grim-face Mr. Johnson declared in Parliament, rejecting yet another call for his resignation.
For all the drama in Parliament, the real action on Wednesday occurred out of sight, where Mr. Johnson’s dwindling band of supporters and growing gang of adversaries maneuvered. One of his key allies, Michael Gove, told the prime minister in a private meeting that the time had come for Mr. Johnson to go. Later Wednesday, the BBC reported that Mr. Johnson had fired Mr. Gove.
Later on Wednesday, Britain’s attorney general, Suella Braverman, called for Mr. Johnson to step down and said she would stand for election to replace him if he did. “If there is a leadership contest, I will put my name into the ring,” she said on the network ITV.
The latest chapter in the crisis began on Tuesday when two senior ministers abruptly resigned: the chancellor of the Exchequer, Rishi Sunak, and the health secretary, Sajid Javid. The trigger was Mr. Johnson’s handling of a case involving Chris Pincher, a Conservative lawmaker who admitted having been drunk at a private members’ club in London where, it was alleged, he groped two men.
Their departures broke open a rebellion against Mr. Johnson within his party that has been building against him for months, fueled by a stream of embarrassing reports of social gatherings at Downing Street that violated the government’s own coronavirus lockdown rules.
Given the speed with which Mr. Johnson’s government is unraveling, many Tory lawmakers believe that Mr. Johnson needs to be replaced quickly to mitigate the electoral damage to the party.
The opposition leader, Keir Starmer, excoriated Mr. Johnson and the cabinet ministers who have yet to abandon the prime minister after a seemingly endless stream of scandals.
“Anyone quitting now, after defending all that, hasn’t got a shred of integrity,” said Mr. Starmer, the Labour Party leader, staring balefully across a table at Mr. Johnson. “Isn’t this the first recorded case of the sinking ship fleeing the rats?”
