Last week, the Labour Party overtook the Conservatives for the first time since the election in a poll conducted by the firm Opinium. The Labour leader, Sir Keir Starmer, also outperformed Mr. Johnson by four percentage points on the question of which leader would make the best prime minister.
Behind Mr. Johnson’s political travails are murmurings about his personal life — that he has complained of being under financial strain since a recent divorce from his second wife. As prime minister, Mr. Johnson earns about £150,000 a year, but he used to make far more as a newspaper columnist, book author and paid speaker. The Times of London has reported that he took a pay cut of more than £670,000, about $860,000, to become prime minister.
Downing Street has flatly denied reports describing a glum prime minister with money woes.
But even his once-loyal supporters in the news media write about his subdued demeanor in a wistful tone. “What on earth happened to the freedom-loving, twinkly-eyed, Rabelaisian character I voted for?” Toby Young wrote in a column for The Spectator, a political magazine Mr. Johnson once edited.
While the Conservative Party has a history of turning against even legendary leaders when its fortunes slide — most famously, Margaret Thatcher in 1990 — few people are ready to bet against Mr. Johnson.
“Most prime ministers end up dealing with something that they were not expecting, and he’s in the process of learning,” said Andrew Gimson, another of Mr. Johnson’s biographers.
The prime minister remains the dominant political figure in Britain, with no rivals in the government — save, perhaps, the chancellor of the Exchequer, Rishi Sunak, who has become popular for his imaginative handling of coronavirus bailout funds.
Given the single-minded ambition that propelled Mr. Johnson to Downing Street, Mr. Gimson dismissed suggestions that he would cave in to pressure and relinquish the job he has sought for most of his adult life.