ASHTON-IN-MAKERFIELD, England (AP) — Labour's Andy Burnham, the popular mayor of Greater Manchester, won a special election for a seat in Parliament and signaled Friday that he will use it to challenge embattled Prime Minister Keir Starmer for leadership of the country.

Burnham decisively won the seat of Makerfield in northwestern England over Rob Kenyon of the anti-immigration party Reform UK. He called his victory a chance for Britain "to turn the tide."

The result cements the status of Burnham, a 56-year-old politician nicknamed the King of the North, as the top contender to replace Starmer as leader of the Labour Party and the country. Burnham won almost 55% of the 45,510 votes cast for a field of more than a dozen candidates, over 9,000 more than runner-up Kenyon.

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Burnham's acceptance speech left no doubt that he wants to lead the country, and not just be one of the more than 400 Labour lawmakers in the 650-seat House of Commons.

"Everyone knows that politics isn't working," he said. "Everyone can feel that the country isn't where it should be. Tonight could, just could, be the turning point."

Starmer congratulated Burnham, writing on X that voters "chose Labour's campaign of hope and optimism over division and hate."

But the prime minister insisted he would fight any attempt to oust him.

"Yes, I will run, I will stand," if there is a Labour leadership contest, Starmer said. "I've said repeatedly I'm not going to walk away from that."

Burnham says he's the candidate of change

Burnham has led Manchester since 2017, overseeing rapid regeneration for the city where the Industrial Revolution was forged. He is pledging to repeat his signature brand of "Manchesterism" on a national scale.

Burnham said he would work to ensure that "the name Makerfield is forever synonymous with bringing about the change this country needs."

He told supporters and campaign workers on Friday that "we are going to lay out a new path for Britain."

"We need an economy that works for everybody, not a few in far-off places from here," he said. "We have an opportunity to turn the tide, to make the country feel like it's working again, to make people see that politics can make a positive difference, to make people feel hope again."

Earlier, in his victory speech, he said Labour had "a final chance to change" and win back voters' trust.

"But it is a chance now, from this result tonight, to build a new politics based on unity and hope, turning away from the path that takes us to a divided, dark politics of the kind we see in the United States," he said.

Voters in Makerfield, who have been the focus of international media attention during the five-week campaign, were aware their votes carried unusual weight.

"I voted Andy Burnham because I don't believe Keir Starmer has done a good job," said Ernest Sherman, 70. "So I voted tactically knowing that Andy Burnham has a chance to replace Starmer. So it will still be Labour, but he will have different views."

Labour is in power but unpopular

Starmer's popularity has cratered since he led the center-left Labour Party to a landslide election victory in July 2024.

He has struggled to deliver promised economic growth, repair tattered public services and ease the cost of living, and been hamstrung by repeated missteps, including his decision to appoint Peter Mandelson, a scandal-tarnished friend of Jeffrey Epstein, as the U.K. ambassador to the United States.

Labour is losing liberal voters to the growing Green Party, and facing a rising Reform UK, which consistently leads in nationwide opinion polls. The Nigel Farage -led party has rapidly gained ground in post-industrial northern England areas like Makerfield, some 200 miles (320 kilometers) northwest of London.

Burnham's resounding victory gives Labour new hope of stopping the Reform tide. Farage acknowledged he was "disappointed, no question about it," with the result.

A dismal performance by Labour in May's local elections spurred scores of lawmakers to demand Starmer's resignation. Wes Streeting resigned as health secretary in May, saying that "where we need vision, we have a vacuum." Streeting has said he will run in a leadership contest if there is one.

Then Josh Simons, the Labour lawmaker for Makerfield, stepped down to trigger a special election and give Burnham the chance to return to Parliament.

Britain's parliamentary system allows governing parties to change leaders midterm, with the winner becoming prime minister without the need for a national election. Under Labour rules, a lawmaker can challenge the leader if they have backing from a fifth of the party's House of Commons lawmakers — a number that stands at 81.

Rob Ford, professor of political science at the University of Manchester, said defeating Reform UK strengthens Burnham's claim to be Labour's biggest asset.

"The narrative he can bring is, 'No one else could have won that seat. I won that. I bring something unique. I bring an ability to renew our appeal,'" Ford said.

Burnham's victory piles pressure on Starmer to quit

Burnham will head to London to be sworn in as a lawmaker as soon as Monday. He's likely to seek a meeting with Starmer to argue that the prime minister should exit gracefully and set a timetable for his departure.

Labour lawmaker Louise Haigh, a Burnham ally, said Starmer should "do what's best for both the country and the Labour Party" and "consider an orderly and managed transition."

"Andy won't be doing anything rash or hasty," she told Sky News. "I'm really hopeful the prime minister and Andy can come to an agreement."

Starmer insisted on Friday that he was elected on a "mandate for change" and would carry on with it.

Earlier this week he suggested that he could offer Burnham a Cabinet post, an idea rebuffed by Burnham's allies.

Despite his stubborn determination, Starmer could be forced out if several members of the Cabinet tell him the game is up and quit, or threaten to quit, in protest.

There could then be a leadership contest, or a coronation, depending on whether other potential candidates think Burnham has an unassailable lead.

"When things begin to slide away from a prime minister, they begin to slide away very, very quickly," said Tim Bale, professor of politics at Queen Mary University of London.

"Over the weekend there will be all sorts of talks behind closed doors, mainly I suspect people trying to persuade Keir Starmer ... that the game is up."

Lawless reported from London. Associated Press writer Danica Kirka contributed to this story.