LONDON  — British Prime Minister Boris Johnson suffered a double blow as voters rejected his Conservative Party in two special elections dominated by questions about his leadership and ethics.

He was further wounded when the party’s chairman quit after the results came out early Friday, saying Conservatives “cannot carry on with business as usual.”

The centrist Liberal Democrats overturned a big Conservative majority to win the rural southwest England seat of Tiverton and Honiton, while the main opposition Labour Party reclaimed Wakefield in northern England from Johnson’s Tories.

Labour candidate Simon Lightwood speaks to media, after winning the Wakefield by-election in Wakefield, West Yorkshire on Friday. Danny Lawson/PA via Associated Press

The contests, triggered by the resignations of Conservative lawmakers hit by sex scandals, offered voters the chance to give their verdict on the prime minister just weeks after 41% of his own MPs voted to oust him.

“The people of Tiverton and Honiton have spoken for Britain,” said the area’s newly elected Liberal Democrat lawmaker, Richard Foord. “They sent a loud and clear message: It’s time for Boris Johnson to go, and go now.”

Defeat in either district would have been a setback for the prime minister’s party. Losing both increases jitters among restive Conservatives who already worry the ebullient but erratic and divisive Johnson is no longer an electoral asset.

Party chairman Oliver Dowden resigned, saying “our supporters are distressed and disappointed by recent events, and I share their feelings.”

“We cannot carry on with business as usual,” said Dowden, previously a staunch Johnson loyalist. “Somebody must take responsibility and I have concluded that, in these circumstances, it would not be right for me to remain in office.”

“I will, as always, remain loyal to the Conservative Party,” he said, without offering an endorsement of Johnson.

The prime minister was 4,000 miles (6,400 kilometers) away at a Commonwealth summit in Rwanda as the results were announced.

The electoral tests came as Britain faces the worst cost-of-living crisis in a generation, with Russia’s war in Ukraine squeezing supplies of energy and food staples at a time of soaring consumer demand while the coronavirus pandemic recedes.

Speaking in Kigali, Johnson acknowledged the results had been “tough,” and said he would “listen to what people are saying, in particular to the difficulties people are facing over the cost of living.”

Johnson won a big majority in a 2019 general election by keeping the Conservatives’ traditional voters — affluent, older and concentrated in southern England — and winning new ones in poorer, post-industrial northern towns where many residents felt overlooked by governments for decades.

Thursday’s elections brought defeat on both fronts. Rural Tiverton and Honiton has voted Conservative for generations, while Wakefield is a northern district that the Tories won in 2019 from Labour.

Labour’s widely expected victory in Wakefield — whose previous Conservative legislator resigned after being convicted of sexual assault — is a boost to a party that has been out of office nationally since 2010.

Labour leader Keir Starmer said it showed the party “is back on the side of working people, winning seats where we lost before, and ready for government.”

Pollsters had said the Tiverton and Honiton race was tight, but the Liberal Democrats overturned a 24,000-vote Conservative majority to win by more than 6,000 votes. The election was called when the district’s Conservative lawmaker resigned after being caught looking at pornography in the House of Commons chamber.

Even with the defeats, which erode his already shaky authority among his own lawmakers, Johnson his party holds a large majority in Parliament. But Conservatives are increasingly concerned that the qualities that led them to make Johnson their leader — including a populist ability to bend the rules and get away with it — may now be a liability.

Ethics allegations have buffeted the prime minister for months, culminating in a scandal over parties held in government buildings while millions of others were banned from meeting friends and family during coronavirus lockdowns.

Johnson was one of 83 people fined by police for attending the parties, making him the first prime minister found to have broken the law while in office. A civil servant’s report on the “partygate” scandal said Johnson must bear responsibility for “failures of leadership and judgment” that created a culture of rule-breaking in government.

He survived a no-confidence vote by his own party this month but was left weakened after 41% of Conservative lawmakers voted to remove him.

Under party rules, Johnson can’t face another such vote for a year, but Friday’s defeats will increase pressure to change that.

“These are pretty dire results,” said Conservative lawmaker Geoffrey Clifton-Brown, a senior member of the committee that oversees party no-confidence votes.

“Serious discussions will be had in the next few days and weeks and then we will all have to make difficult decisions,” he said.

Johnson also faces a parliamentary ethics probe that could conclude he deliberately misled Parliament over “partygate” — traditionally a resigning offense.

Conservative lawmaker Roger Gale, a long-time Johnson critic, reiterated his calls for the prime minister to quit now.

“The soul of our party is at stake,” he said.