The Green Party has achieved a groundbreaking win in the Gorton and Denton by-election, delivering a new challenge to Sir Keir Starmer’s leadership.

This marks the Greens’ first-ever victory in a parliamentary by-election, highlighting their rising prominence as a formidable Left-wing competitor to Labour, which suffered an embarrassing third-place finish in the Greater Manchester seat.

Labour’s significant loss in what was once considered a stronghold is likely to fuel speculation regarding Sir Keir’s position as Prime Minister, with critics increasingly dubbing him a ‘lame duck leader.’

This setback is particularly stinging for Sir Keir, who personally campaigned in the area earlier this week, only to see Labour trail behind both the Greens and Reform UK.

His leadership has already been under scrutiny due to the recent Peter Mandelson scandal, with growing unrest among Labour MPs over their party’s poor polling performance.

The defeat in Gorton and Denton intensifies concerns about Labour’s dwindling support, as they lose ground to the Greens on the Left and to Reform on the Right.

Sir Keir and Labour won Gorton and Denton at the 2024 general election with more than half the vote.

But, less than two years on, the Greens have overturned Labour’s majority of more than 13,000 votes to give themselves a fifth MP in the House of Commons.

Victorious by-election candidate Hannah Spencer, a plumber, will also become only the sixth-ever Green MP of all time.

She secured 14,980 votes to win the seat with a 4,402-vote majority ahead of Reform candidate Matthew Goodwin (10,578 votes), and Labour’s Angeliki Stogia (9,364 votes).

The Greens, led by ‘eco-populist’ Zack Polanski, pitched themselves during the by-election campaign as the only option for anti-Reform UK voters.

In the early hours of Friday, before the official result was announced, a deflated Labour deputy leader Lucy Powell admitted the Greens had ‘managed to win the argument that they were best placed’ to beat Nigel Farage’s party.

‘I wanted Angeliki Stogia to be my colleague in Parliament,’ Ms Powell told Sky News.

‘But I think what is really clear is that there is a big majority in this constituency that hasn’t voted for Reform.

‘And on the day the Greens have managed to win that argument that they were best placed to do that.

‘But I’m not sure whether that would totally translate in a general election.’

As well as pitching themselves as the best anti-Reform option in the by-election, the Greens also attempted to appeal to the significant Muslim vote in Gorton and Denton by hammering Sir Keir and Labour over Gaza.

The seat is sharply divided in ethnicity, religion and deprivation – which made the outcome incredibly difficult to predict.

Responding to her party’s defeat, Labour chairwoman Anna Turley said: ‘This result is clearly disappointing.

‘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.’

A Conservative spokesman said: ‘Keir Starmer has killed the Labour Party.

‘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.’

Prior to the result being announced in the early hours of Friday, a furious row broke out over claims of ‘high levels’ of illegal ‘family voting’. 

Democracy Volunteers, who sent accredited observers across Gorton and Denton on Thursday, expressed fears about major breaches of electoral law.

Family voting is where a voter is accompanied by another person into or near polling booths with the intention of influencing their vote.

Tougher legislation, known as the Ballot Secrecy Act, was introduced in 2023 in a bid to clamp down on the practice.

It made it more clearly an offence for someone to accompany a voter to a polling booth or position themselves nearby with the intention of influencing a voter.

In a statement issued as polls closed on Thursday night, Democracy Volunteers said they had seen ‘the highest levels of family voting at any election in our 10-year history of observing elections in the UK’.

But Manchester City Council insisted ‘no such issues have been reported’.

Labour chair Anna Turley said the reports of family voting were ‘extremely worrying and concerning’.

Mr Farage said it ‘raises serious questions about the integrity of the democratic process in predominantly Muslim areas’.  

Mr Polanski told BBC Newsnight: ‘I think it’s important that there’s full transparency about the democratic process.

‘And if the recommendation is that there should be an inquiry or further steps then yes I’d support that.’

A final photocall for Ms Stogia on Thursday saw her join forces with Ms Powell and Greater Manchester mayor Andy Burnham.

In pouring rain in Gorton as the campaign counted down to its final hours, the three stepped onto a campaign bus along with activists for a final round of door-knocking.

Mr Burnham said he was not ‘sorry’ he was not the by-election candidate himself, with his bid to contest the seat for Labour dramatically blocked by Sir Keir last month.

‘No, we’ve got a brilliant candidate, and she hasn’t put a foot wrong,’ he said. ‘She’s been out every day. She’s done us proud.’

The Greater Manchester mayor is widely seen as a potential leadership challenger to Sir Keir should he return to Westminster as an MP.

Mr Farage visited Gorton and Denton on Wednesday night, speaking to voters alongside Reform candidate Matthew Goodwin.

Ahead of polls opening at 7am on Thursday, Mr Farage said: ‘Our message on election day is clear.

‘The Prime Minister is panicking and knows he has broken his promises to the British people. Vote Reform to ditch Starmer.’

The PM made a token visit to the constituency on Monday but was humiliatingly kept away from ordinary voters amid dire poll ratings. 

The premier barely survived a leadership coup a fortnight ago, with the Cabinet only rallying round at the last moment. 

In his final message to voters, Sir Keir sought to woo wavering Labour voters by painting the contest as a straight fight between his party and Reform.

He said: ‘The choice at today’s by-election could not be more stark. Unity or division.

‘Driving down the cost of living with Labour or driving a wedge between communities under Reform.

‘Moving forwards together, or opening up anger and division that holds our country back.

‘Reform’s Matthew Goodwin thinks people who aren’t white can’t be English and wants women who choose not to have children to pay more tax.

‘Vote Labour in Gorton and Denton today to send him and his toxic politics packing.’

The contest in Manchester had been beset by allegations of dirty tricks, with parties repeatedly referring each other’s candidates to the police.

In the latest twist, the Greens accused Labour of handing out leaflets from an ‘entirely fictitious’ tactical voting organisation urging voters to back Sir Keir’s party.

The leaflets from ‘Tactical Choice’ carried a supposed poll that put Labour and Reform neck-and-neck when ‘not including polling funded by Green Party donors’.

They added: ‘Based on a new prediction published in the last 24 hours we are recommending voting Labour.’

A Green Party spokesman said: ‘In a final throw of desperation, Labour have made up an entirely fictitious organisation called ‘Tactical Choice’ referencing them on their final leaflet.

‘They’ve had to make this up because every actual tactical voting organisation has endorsed the Green Party as the best hope to keep Reform out in this election.’

For its part, Labour accused the Greens of ‘whipping up hatred’ over Gaza in parts of the constituency with a large Muslim population.

The party even put out a campaign video in Urdu which featured images of David Lammy shaking hands with Israeli PM Benjamin Netanyahu.

Ms Powell said the Green campaign had been ‘characterised by misinformation, with dodgy bar charts’.

However, Labour put out a leaflet of its own with a bar chart showing it neck-and-neck with Reform – but omitting the Greens in the lead.