The Green Party has won a by-election for the first time ever, with Reform UK finishing in second.

Labour, the party of government, who had held the seat came third.

Our political editor Chris Mason says Keir Starmer has spent much of his time as prime minister fretting about the rise of one insurgency, Reform UK, broadly on the right.

Now, Chris says, Starmer has to fear the reality of an insurgency broadly on the left - from the Green Party.

Watch his snap analysis - from Manchester - below:

Green Party's historic success means future of British politics is more uncertain than everpublished at 06:25 GMT

06:25 GMT

Professor Sir John Curtice
Polling expert

Image source, EPA

Hitherto, the Greens had never won more than 10% of the vote in a parliamentary by-election, a figure they reached in the Somerton and Frome by-election in 2023.

Now Hannah Spencer has already claimed her place in the history books as the first ever Green candidate to win a parliamentary by-election.

Not only did Spencer win, but she won well, significantly outperforming the expectations of the polls.

Rather than winning narrowly, the party won 40.7%, enough to put them as much as 12 points ahead of second placed Reform. It represented as much as a 27.5 point increase on the party's share in 2024.

Labour, who had not hitherto lost an election in the area since 1931, fell into third place. The party's 25.4% of the vote represented a near halving of their 50.8% of the vote in 2024 and the 13th biggest ever fall in the party's support in a by-election.

Meanwhile, the Conservatives lost their deposit with just 1.9% of the vote, their worst ever by-election result.

Apart from the exceptional circumstances of the Rochdale by-election in 2024, when Labour disowned their candidate, leaving George Galloway to defeat a second-placed independent candidate, it is the first time that neither Labour nor the Conservatives have been one of the top two parties in a by-election contest.

With the two parties both running at 20% or less in the polls, the Conservative-Labour duopoly that has long dominated post-war British politics has never looked weaker.

The Conservatives are struggling to fend off the challenge from Reform, and now, at the other end of the spectrum, Labour's traditional position of the principal party of the left of British politics is evidently under threat from the Greens.

Doubtless the result will raise fresh questions in Labour MPs minds as to whether Keir Starmer should remain prime minister.

• Continue reading my analysis here

Image source, PA Media

Hannah Spencer has made history as the first Green Party candidate to win a Westminster by-election - as well as becoming the party's first MP in northern England.

The 34-year-old currently leads the Greens on Trafford Council, where she has represented the Hale ward since May 2023.

She has previously said she's worked as a plumber since she was 16, and during her victory speech added she qualified as a plasterer two weeks ago.

"I didn't grow up wanting to be a politician. I am a plumber," she said during her speech. "I am no different to every single person here in this constituency. I work hard. That is what we do."

Spencer also stood in the 2024 Greater Manchester mayoral election, and is the owner of four greyhounds - who she took on the campaign trail.

Image source, PA Media

Image source, EPA

The Green Party's Hannah Spencer has won the Gorton and Denton by-election, becoming the first Green candidate to win a Westminster by-election - as well as the party's first ever MP in northern England.

• Spencer won 14,980 votes, making up nearly 41% of the votes cast. Reform UK's Matt Goodwin came second, with 10,578, while Labour's Angeliki Stogia came third with 9,364
• In her victory speech, Spencer vowed to fight for working people, while calling out "divisive figures" who she said "scapegoat" others
• The 34-year-old plumber also apologised to customers who have booked her as "I'm heading to Parliament"
• Labour Party chair Anna Turley called the result "clearly disappointing" - BBC election expert Sir John Curtice says the result is going to make life for Keir Starmer "even worse"
• Reform's Matt Goodwin says his party "embarrassed Labour" but also hit out at the Greens, accusing them of "riding a dangerous wave"
• Earlier, election observers say they witnessed "concerningly high" levels of "family voting" at polling stations - a claim disputed by the council

A spokesperson for the Conservatives - the party came fourth with 706 votes - says Keir Starmer has "killed the Labour Party".

The spokesperson adds: "In losing one of Labour's safest seats, in a constituency that has returned Labour MPs for almost a century, Starmer has shown he no longer commands the support of Labour voters and is now a lame duck leader.

"This result shows the Labour government now lacks any support in the country and has no mandate for the terrible policies it is pursuing - increasing the benefits bill, raising taxes, weakening our borders and the armed forces.

"Only the Conservatives have the experience, the plans and the team to ensure a stronger economy and a stronger country."

Image source, EPA

Green leader Zack Polanski says "almost half" of Labour's 2024 general election voters "abandoned them", as "many switched to voting Green".

"The Green Party saw a record-breaking swing in our direction and more than tripled our vote," he says.

He adds: “If we see a swing like this at the next general election, there will be a tidal wave of new Green MPs.

"When I was elected leader of the Greens I said we were here to replace Labour and I meant it. Hannah was a fantastic candidate and I know she’ll make a brilliant MP."

He also accuses Labour of fighting "a shameful, dirty campaign".

"They knew they couldn’t win, but they risked splitting the vote and letting Reform in," he says, adding: “People everywhere will now know that voting Green is the way to defeat Reform."

Image source, PA Media

Labour candidate Angeliki Stogia declined to speak to the media as she left the count, say reporters in Manchester.

Meanwhile, Labour Party chair Anna Turley has called tonight's result "clearly disappointing".

The constituency had historically been considered a Labour safe seat.

Turley says: "By-elections are normally difficult for the party of government, and this election was no different.

"We have had thousands of conversations over the last few weeks and we know the majority of voters here did not want the poisonous politics of Nigel Farage and Reform.

"We will continue to deliver a programme for government that tackles the cost of living crisis families are facing, creates opportunities for young people and invests in our public services.

"The politics of anger and easy answers offered by the Greens and Reform won't deliver this.

"We will move forwards with a relentless focus on delivering the renewal communities across Britain want to see."

Image source, Getty Images

Reform UK's Matt Goodwin, who came second behind the Greens, says Reform UK has "embarrassed Labour in one of their strongest seats."

"Sixth safest Labour seat. And I think if we can do this here, we can do this pretty much anywhere," he says after the party knocked Labour into third place.

Of the Greens, he accuses the party of "riding a very dangerous wave".

"I'm very concerned about the direction of the country. And I think many people are going to be watching this by-election, and they're going to be feeling the same thing that I am, which is deep concern about where Britain is heading.

"I think the progressives were told how to vote, and I think what you saw was a coalition of Islamists and woke progressives that came together to dominate a constituency.

"And many people in this country will look at Gorton and Denton and be appalled by what they see."

Image source, Reuters

More now from Hannah Spencer, Westminster's newest MP. She won the vote tonight by more than 4,000 votes.

It is "really clear" that people are "ready for something different", she says. She says people are "rejecting the political parties that have always shut us out".

People have voted for "someone like me, who is actually just pretty normal", she says.

Commenting on the Green campaign, she adds: "All we have done is... listen to people."

Asked what the party stands for, she says "social justice issues". That includes climate issues, but also things like the cost of living, she says.

These issues "can be fixed" but "politicians for too long have ignored" them, she says.

The BBC's election expert Sir John Curtice says the surprising part of the result is the scale of the Green Party's victory.

"They have actually managed to win nearly 41% of the votes cast in this constituency," he says. "The truth is that the Greens have to be congratulated on what is quite a remarkable performance."

He says the result is going to "make life for Keir Starmer even worse".

"It's not just that Labour have lost, they've lost badly... they trail the Greens by 15 points."

Image source, PA Media

We can now bring you the full voting tallies:

• Green Party - 14,980
• Reform UK - 10,578
• Labour Party - 9,364
• Conservative Party - 706
• Liberal Democrats - 653
• Monster Raving Loony Party - 159
• Advance UK - 154

• Rejoin EU Party - 98
• Libertarian Party - 47
• Social Democratic Party - 46
• Communist League - 29

The total number of votes cast was 36,814, with a voter turnout of over 47%.

More now from the Green Party's Hannah Spencer, who is delivering her victory speech.

"Our struggles might not be the same... but we stick up for each other," she tells the people of Gorton and Denton.

"Earning your trust starts now," she says, adding that she will "work hard" for those who didn't vote for her too.

She calls out "politicians and divisive figures" who she says "scapegoat" others, saying people have "underestimated how similar we all actually are".

To those who feel "left behind", she says: "I see you and I will fight for you".

Spencer then apologises to any customers who have booked her in for plumbing jobs. "I'm heading to Parliament," she says.

Hannah Spencer is now speaking. She starts by saying she didn't grow up "wanting to be a politician" and adds that two weeks ago, "I also qualified as a plasterer".

"Even under chaos, even under pressure, I get things done. I am no different from every single person in this constituency," she says.

She says working hard "used to get you something" but says people are now struggling.

"Life has changed. Instead of working for a nice life... we're working to line the pockets of billionaires. We are being bled dry," she says.

"I think everybody should get a nice life. Clearly I'm not the only person who thinks that."

Here are the vote counts for the candidates in first, second and third place:

• Hannah Spencer (Green Party): 14,980 votes
• Matt Goodwin (Reform UK): 10,578 votes
• Angeliki Stogia (Labour Party): 9,364 votes

We'll bring you the counts for the full list of candidates shortly.

The Green Party's Hannah Spencer has won the Gorton and Denton by-election.

We'll bring you more on this result soon.

The returning officer is now on stage, about to read out the vote tally for each candidate.

You can watch the count live at the top of the page.

We'll bring you the result shortly.

Green Party candidate Hannah Spencer has just arrived at the count, amid speculation she is about to win the by-election.

Kevin Fitzpatrick
Greater Manchester political reporter

The candidates from the big three parties have begun arriving in anticipation of the result being announced.

Labour’s Angeliki Stogia was first, putting a brave face on and flanked by Lucy Powell. She was quickly surrounded by supportive colleagues wearing red rosettes.

Next was Reform UK’s Matt Goodwin, who slid past photographers with his team, senior party figures notable by their absence.

The crowd at the entrance though is waiting for the apparent winner to walk through. Still not announced, it appears all but certain that the Green Party’s Hannah Spencer will arrive soon, ready to be confirmed as Gorton and Denton’s next MP.

Image source, Reuters

Image source, Reuters

Image source, Reuters

Jack Fenwick
Political correspondent

From a Green Party source: "It's looking like Labour are in third and they only have themselves to blame for failing to deliver any change in government. Voters are tired of them and turning to what the Greens are offering."

We can now see the podium being set up in Manchester - although no returning officer is visible yet. This could suggest we are getting closer to the result being announced.