U.K. Prime Minister Boris Johnson’s Conservative Party picked up a major victory on Friday, winning a seat in the northeast town of Hartlepool -- a seat held by the opposition Labour Party since it was formed and a brick in Labour’s now-crumbling "red wall."

Conservative candidate Jill Mortimer secured nearly 52% of the vote, while Labour candidate Paul Williams only received around 29%.

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"Labour have taken people in Hartlepool for granted for too long," Mortimer said in her victory speech.

British Prime Minister Boris Johnson speaks to the media next to a large inflatable of him and flanked by Jill Mortimer, the winning Conservative Party candidate of the Hartlepool by-election on May 7, 2021.(AP Photo/Scott Heppell)

British Prime Minister Boris Johnson speaks to the media next to a large inflatable of him and flanked by Jill Mortimer, the winning Conservative Party candidate of the Hartlepool by-election on May 7, 2021.(AP Photo/Scott Heppell)

Johnson’s Tories had crushed Labour in the 2019 general election in part by taking key seats in areas in the North, Middle England and Wales that had voted Labour for generations. Seats like Burnley, Wrexham and Stoke-on-Trent all turned Tory blue.

Both the issue of Brexit, which Johnson promised to deliver on and which was popular with many traditionally Labour-supporting working class voters in the North of the country, and the Labour Party’s swing to the hard left under then-leader Jeremy Corbyn were seen as key reasons for Labour’s crushing defeat.

Since then, Corbyn was replaced by the more moderate Keir Starmer, who has sought to bring the party more to the center. The issue of Brexit was mostly resolved and was eclipsed in mid-2020 by the coronavirus pandemic.

However, even after a year in which Johnson was widely criticized for his handling of the lockdowns, both by those who thought he didn’t go far enough and those who thought them too strict, and saw an economic downturn, the Conservatives still managed to clinch the seat in Hartlepool.

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On Friday, Johnson hailed both Brexit and the rollout of the COVID-19 vaccines as keys to victory. That rollout has been in sharp contrast with the disastrous rollout by the European Union -- something that Brexit supporters have noted.

"What has happened is that they can see we did get Brexit done," Johnson said during a visit to the town on Friday, where he posed next to an inflatable of himself. "What people want us to do now is to get on with delivering on everything else. Number one is continuing the vaccine rollout, making sure that we go from jab to jab, to jab to jobs, jobs, jobs."

Britain's opposition Labour Party leader Keir Starmer leaves his home in London on May 7, 2021, following the declaration that the Labour Party has lost the Hartlepool parliamentary election. (Stefan Rousseau/PA via AP)

Britain's opposition Labour Party leader Keir Starmer leaves his home in London on May 7, 2021, following the declaration that the Labour Party has lost the Hartlepool parliamentary election. (Stefan Rousseau/PA via AP)

The Tory victory is likely to increase pressure on Starmer, and the Labour Party in general, which has seen its traditional working class support crater as it turned more radically left under Corbyn and has continued to be split by identity politics and "woke" issues --- popular among left-wing activists but unpopular with many of its voters. Starmer has faced pushback from the left and accusations of being too bland against the more boisterous Johnson.

Starmer’s lack of impact on the electorate was demonstrated in a TV moment this week in which a Sky News reporter stopped a voter in Hartlepool and pointed to the Labour leader, who was visiting the town, and asked if she knew who he was -- to which the woman said she didn’t.

"It’s Keir Starmer," the reporter said.

"Right," the woman responded flatly. "No idea."

Those in the "Blairite" wing of the party are likely to urge Starmer to keep going in distancing the party from the Corbynite left; Corbyn’s allies were already sharpening their knives -- noting that even Corbyn managed to hold the Hartlepool seat.

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"Crushing defeat for Labour in Hartlepool," former Shadow Home Secretary Diane Abbott, a key Corbyn ally, tweeted. "Not possible to blame Jeremy Corbyn for this result. Labour won the seat twice under his leadership. Keir Starmer must think again about his strategy."

There were, however, some highlights for the Labour Party. London and Manchester Mayors Sadiq Khan and Andy Burnham were on track to win reelection, while the Labour government in Wales is expected to stay in power.

The Associated Press contributed to this report.