LONDON — Contenders to succeed Boris Johnson, Britain’s scandal-scarred prime minister, were already jockeying for position on Friday as his wounded party wrestled with the question of whether to allow him to remain a caretaker until his replacement is chosen, a task that could stretch through the summer.
A day after Mr. Johnson reluctantly announced his departure, Tom Tugendhat, a centrist lawmaker, said that he would run to replace him, while Suella Braverman, the attorney general, had declared her interest in the job even before Mr. Johnson quit.
Neither is seen as a front-runner in a highly unpredictable Conservative leadership contest. Under the British system, the party with the most lawmakers in Parliament gets the chance to form a government, and if it switches its leader, that person can become the new prime minister without necessitating a general election.
Embroiled in a new scandal over his handling of sexual assault allegations against a lawmaker, Mr. Johnson — who had previously fended off several other scandals — fought desperately to keep his job despite dozens of resignations from his government on Wednesday.
As the exodus of government officials continued into Thursday, Mr. Johnson was ultimately left with no choice but to announce that his often chaotic time in Downing Street, marked by frequent periods of crisis, was drawing to a close.
One question hanging over British politics was resolved on Friday when the police decided not to fine the leader of the opposition Labour Party, Keir Starmer, over allegations that he broke lockdown regulations.
Mr. Starmer, a former chief prosecutor, had promised to resign if he was found to have broken the law — that would have meant leadership contests in both Britain’s main political parties.
Attention will focus on the battle to succeed Mr. Johnson, however, and the list of his would-be successors will probably grow in the coming days, with several high-profile figures expected to declare their interest. They include the foreign secretary, Liz Truss; the chancellor of the Exchequer, Nadhim Zahawi; Mr. Zahawi’s predecessor as chancellor, Rishi Sunak; and two former health secretaries, Sajid Javid and Jeremy Hunt. Steve Baker, a former minister and Brexit hard-liner, has also suggested that he will join the race.
While those potential candidates battle it out, Mr. Johnson appeared likely to extend his stay in Downing Street for several weeks, leading a lame-duck cabinet that has promised not to embark on new policy initiatives until he quits.
Mr. Johnson has resisted calls for him to step aside immediately, an idea backed by, among others, a former Conservative prime minister, John Major. But after promising on Thursday to quit, Mr. Johnson persuaded enough senior lawmakers to help him form a stopgap cabinet, allowing him to continue in an interim capacity.
When Mr. Johnson’s predecessor, Theresa May, agreed to step down, there was little debate about her decision to continue as a caretaker until her successor was chosen.
The circumstances surrounding Mr. Johnson’s departure are very different though, because he was ousted under a cloud of scandal that raised serious questions about his honesty and integrity. His refusal to stand aside immediately has infuriated the opposition Labour Party, which has threatened to demand a no-confidence vote in Parliament against the government.
“How many more months of chaos must we endure?” wrote Angela Rayner, the deputy leader of the Labour Party, in an opinion article in the Daily Express.
“Enough is enough.” she added. “The public is fed up with the lies, lawbreaking and sleaze.”
But for the Conservatives, agreeing to a no-confidence motion would carry huge risks: If it passes, Britain would be plunged into a general election at a time when the party is struggling in the polls. As such, and with Conservative lawmakers holding easily the biggest number of seats in Parliament, that scenario seems implausible.
The length of time that Mr. Johnson remains in Downing Street will most likely be determined by the results of the Conservative leadership contest, whose timetable is expected to be agreed on Monday. That sets the stage for Conservative lawmakers to select their two top candidates, with the ultimate choice being made by dues-paying members of the party.
Contenders will probably include those aiming to raise their profiles and auditioning for cabinet jobs, as well as the more serious candidates.
The absence of a clear favorite could encourage other senior Conservative politicians to try their chances. That group includes the defense secretary, Ben Wallace; the home secretary, Priti Patel; the transport secretary, Grant Shapps; and Michael Gove, who was a member of the cabinet as recently as Wednesday.
The Fall of Boris Johnson, Explained
Turmoil at Downing Street. Britain’s prime minister Boris Johnson said he would step down less than three years after his landslide election victory, following a series of scandals that have ensnared his government. Here’s what led to this:
Mr. Gove is a friend and rival of Mr. Johnson’s from their days at Oxford University. They were among the most prominent backers of Brexit, but Mr. Gove was fired from the cabinet on Wednesday night after urging the prime minister to quit.
Although the list of candidates could reach double figures, lawmakers are expected to narrow down the field to two before the summer recess, scheduled for July 21.
The final decision will then be left in the hands of around 200,000 members of the Conservative Party. In 2019, when Mr. Johnson won the leadership, he did so after a campaign of several weeks in which he and his rival, Mr. Hunt, attended campaign events around the country.
That second part of the process did not take place in 2016, when David Cameron stood aside after British voters elected to leave the European Union. In the contest to replace him, Andrea Leadsom, one of the two contenders selected by lawmakers, ultimately withdrew, giving Theresa May an unopposed path to Downing Street.
That could happen again and, if so, it would shorten the contest considerably. But in 2016, it produced a leader whose campaigning skills were untested and were then found wanting when Mrs. May called a snap general election the following year. She lost her parliamentary majority, so Conservatives may be reluctant to rush into a quick choice this time round.
Whoever emerges victorious is unlikely to generate as much news as their predecessor, who was still in the headlines on Friday, this time accused of trying to hang on to his job as caretaker partly so that he could hold a delayed wedding party at Chequers, the countryside residence of British prime ministers. Mr. Johnson married his third wife, Carrie Symonds, last year.
His aides have said that Mr. Johnson sees it as his duty to stay on, adding that the venue for the event was being changed. But speaking to the BBC, the education secretary, James Cleverly, said that Mr. Johnson should be allowed to hold his wedding celebration at Chequers regardless of when his successor is elected.
It would be “churlish,” Mr. Cleverly said, “to be negative about two people who want to celebrate their marriage and their love for each other.”