LONDON — Britain’s governing Conservative Party lost two strategically important parliamentary seats in elections in the north and south on Thursday, dealing a harsh blow to Prime Minister Boris Johnson and raising fresh doubts about his scandal-scarred leadership.
Voters in Tiverton and Honiton, a rural stretch of southwest England that is the party’s heartland, and in the faded industrial city of Wakefield evicted the Conservative Party from seats that had come open after lawmakers were brought down by scandals of their own.
In Wakefield, the Labour Party won a widely expected victory, with a comfortable margin over the Conservatives. In the south, which had been viewed as a tossup, the Liberal Democratic Party scored an even more impressive result, overcoming a huge Conservative majority in the last election to win the seat by a solid margin.
The double defeat is a stinging rebuke of Mr. Johnson, who survived a no-confidence vote in his party earlier this month, precipitated by a scandal over illicit parties held at Downing Street during the coronavirus pandemic. It will likely revive talk of another no-confidence vote, though under the party’s current rules, Mr. Johnson should not face another challenge until next June.
In an immediate sign of the political fallout, the chairman of the Conservative Party, Oliver Dowden, resigned on Friday morning. In a letter sent to Mr. Johnson less than two hours after the votes had been counted, Mr. Dowden said the party’s supporters were “distressed and disappointed by recent events, and I share their feelings,” adding that “somebody must take responsibility.”
The defeats exposed Conservative vulnerabilities on two fronts: the so-called “red wall,” the industrial north of England, where Mr. Johnson shattered a traditional Labour stronghold in the 2019 general election, and in the southwest, a traditional Tory stronghold often called the “blue wall.”
It was the first double defeat for a governing party in a parliamentary by-election since 1991. And as grim as the electoral prospects for the Conservatives look, they could worsen further next year, with galloping inflation, interest rate hikes and Britain almost certainly heading for a recession.
In Tiverton, where the Liberal Democrats won 53 percent of the vote to the Conservatives’ 38 percent, the victorious candidate, Richard Foord, said the result would send “a shock wave through British politics.”
The Labour Party leader, Keir Starmer, said the victory in Wakefield, where Labour won 48 percent of the vote to the Conservatives’ 30 percent, was “a clear judgment on a Conservative Party that has run out of energy and ideas.”
While the political contours of the two districts are very different, they share a common element: a Conservative lawmaker who resigned in disgrace. In Tiverton and Honiton, Neil Parish quit in April after he admitted watching pornography on his phone while sitting in Parliament. In Wakefield, Imran Ahmad Khan was sentenced to 18 months in prison in May after being convicted of sexually assaulting a teenage boy.
Mr. Khan’s legal troubles, which included multiple unsuccessful efforts to have his case heard secretly, meant that Wakefield did not have a functioning representative in Parliament for two years. That left people in the city deeply disillusioned, analysts said, not just about Mr. Khan but about politics in general.
“The whole unfortunate situation is about a broken political system that ignores the voters and their wishes and politicians who don’t do the right thing or serve the people who got them into power,” said Gavin Murray, editor of the Wakefield Express. “This point is amplified and exaggerated by the behavior of Boris and Downing Street.”
While there had been little expectation that the Conservatives would hold on to the Wakefield seat, the scale of Labour’s victory there suggested it could compete successfully against the Conservatives in the next general election.
The massive swing in votes in Tiverton and Honiton, where the Conservatives had hoped to hold on, was even more sobering for Mr. Johnson.
The Liberal Democrats’ upset victory, by a convincing margin, in one of the Conservative Party’s safest districts suggested that even the most loyal Tory voters had become disenchanted with the serial scandals and nonstop drama surrounding the prime minister.
Last year, the Conservatives were stunned by the loss of a parliamentary seat in Chesham and Amersham, a well-heeled district northwest of London. Analysts said it suggested a backlash against Mr. Johnson’s divisive brand of politics and tax-and-spend policies.
The government has promised to “level up” and boost the economy in the North of England, a reward to the red-wall voters. But some analysts see a significant risk of support fracturing among traditional Tories in the south.
The Liberal Democrats specialize in fighting on local issues in by-elections. They have a long history of achieving surprise results, and success for them in Tiverton and Honiton consolidated the party’s strong performance in local elections in May, where they also emerged the big winners.
In the days leading up to the two elections, Labour and the Liberal Democrats both concentrated their resources in the districts they were better placed to win, each leaving the other a freer run.
Vince Cable, a former leader of the Liberal Democrats, said that rather than any official cooperation between the two parties, there was a “tacit understanding, relying on the voters to get to a sensible outcome.”
For all the symbolism of the defeats, Mr. Cable said, “in the short run this isn’t going to do Johnson a great deal of harm,” both because the prime minister recently won a confidence vote among his lawmakers and because the defeat was “priced in.”
“Because the economic outlook is so awful, certainly for the next 12 to 18 months, it wouldn’t surprise me if Johnson did something very risky and went for an autumn election,” Mr. Cable said at an election-eve briefing.
Kenneth Baker, a former chairman of the Conservative Party, said that a defeat in Tiverton and Honiton would underscore that “the position is pretty bleak for the Conservative Party,” which won an 80-seat majority in Parliament in the 2019 general election.
“There is a huge opportunity for the Liberal Democrats now because neither the Labour Party nor the Conservative Party have any vision or strategy whatsoever,” said Mr. Baker, who is a member of the House of Lords. Mr. Johnson, he added, is now too polarizing a figure to lead the party successfully.
“If the Conservative Party continues to be led by Boris,” he said, “there is no chance of the Conservatives winning an overall majority.”