Andy Burnham has won the Makerfield by-election paving the way for him to launch a Labour leadership challenge.
The Greater Manchester mayor took the seat by 9,231 votes, seeing off Nigel Farage’s Reform UK who came in second.
Mr Burnham’s victory sets up a potential leadership contest unless Sir Keir Starmer agrees to step down as Prime Minister.
In his victory speech he said his party had a “final chance to change” and “we must act upon it”.
Later at a victory rally he said: “It is our last chance to change, but we’re going to take it, aren’t we? We are going to take that opportunity and we are going to lay out a new path for Britain.”
Sir Keir has insisted he will fight any attempt to oust him and has been building up a war chest for a leadership campaign.
But Mr Burnham’s supporters urged the Prime Minister to set out an “orderly and managed transition” of power.
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Reform still ahead in national polls
According to national polls, Reform UK are still the most popular party in the country, despite Andy Burnham winning for Labour in Makerfield.
In polls conducted in the two weeks up to 18 June, Reform has an average of around 27%, compared to around 19% for each of Labour and the Conservatives.
The Greens and the Liberal Democrats are on an average of 13% and 12% respectively.
Davey: 'Reform can be beaten'
Liberal Democrat leader Sir Ed Davey said the Makerfield by-election showed that “Reform can be beaten”.
Sir Ed said: “Yesterday’s result shows that Reform can be beaten, just as the Liberal Democrats have done in local elections across the country.
“But while Labour fight over the keys to No 10, people are struggling.
“We need real change, not more chaos, starting with a new deal with Europe.”
Streeting ally hints that he has support to fire gun in leadership race.
One of Wes Streeting’s closest allies has hinted that the former health secretary has what he needs to fire the starting gun in a leadership race.
In an interview on Politics Live, Labour MP Melanie Ward said that all of Labour’s leading figures, including Andy Burnham, need to discuss an orderly transition of power in the coming days.
She said: "In the life of any captain of a team … there comes a time when the captain has to hand over the armband - a time when the captain has lost the dressing room."
Ward also said Mr Streeting is "prepared to speak to the other key players and work out a different way through this".
Could Starmer's days be numbered?
Andy Burnham has made no secret of his leadership ambitions and his return to Westminster means a battle is brewing, especially after Sir Keir insisted he would fight off any challenge to his premiership.
But what could happen next?
Andy Burnham could trigger a leadership contest, as could any other Labour MP, provided they have the backing of at least 81 Labour MPs.
As the current leader, Sir Keir would automatically be entered in the contest, though even if that were not the case, the Prime Minister has made clear he is not going down without a fight.
Other contenders include former health secretary Wes Streeting and former Royal Marines officer Al Carns. If Burnham doesn’t trigger a leadership race, Streeting has mooted that he has the support to fire the starting gun.
Josh Simons at Andy Burnham's first speech as MP
Also present at Andy Burnham’s first speech as elected MP in Makerfield was none other than the man who made it all happen - Josh Simons.
Josh Simons resigned as MP in order to trigger the by-election that has led to the return of Andy Burnham to Westminster.
Starmer insists on standing in leadership race after Burnham win
Sir Keir Starmer has insisted that he will stand in a Labour leadership contest.
He said he would not “walk away” from Downing Street, setting Labour up for a showdown in the coming weeks.
“If there is a contest, then yes, I will stand,” he told reporters on Friday.
That depends, of course, on Burnham triggering the contest, though it has been speculated that the Mayor of Manchester will officially launch his challenge within weeks, possibly even days.
Starmer wants to 'take the fight' to Reform
Sir Keir Starmer has told Labour staffers across the country that the party needs to “pull together” and “take the fight” to Reform UK.
In a call today, the Prime Minister said: “The tide is turning on Reform. If you look at the national polling, Reform are now only six or seven points ahead of Labour in the national polls, which two years into a five year parliament is a place that we can make huge advances from.
“The next opportunity is the Greater Manchester Mayoralty, which now will follow as a result of the Makerfield by-election. It’s a chance to go and take the fight to Reform.
“It’s really important, it’s a huge by-election, one of the biggest by-elections we’ll ever run. It is really important that we maintain that Labour mayoralty, and that we take Reform on.
“This is the fight in politics at the moment. We should relish the opportunity to take the fight to Reform and give them a hiding in Manchester, and frankly, expose them for who they are: divisive, inward, wanting to divide our country, the complete opposite values to us.
“Let’s pull together as a party and a movement. The one thing we’ve got to avoid doing is plunging our party and our country into chaos by turning on each other and tearing apart our party and our movement. That has never worked. That’s what the last government did. We need to learn that lesson.”
Backbencher calls for Starmer to step down
A Labour backbencher has called on Sir Keir Starmer to set out his timetable to exit Downing Street following Andy Burnham’s victory in Makerfield.
MP for Normanton and Hemsworth Jon Trickett said: “The north’s voice has been heard.
“Andy Burnham’s win in Makerfield is a victory for the Labour movement as a whole which fought a properly organised campaign to defeat the toxic anti-working class politics of the far right.
“In the wake of the by election, it’s clear that Farage and his hard-right acolytes can be defeated.
“However, there can be no more messing about.
“Keir Starmer has to immediately state a timetable for his departure as leader, as he is an obstacle to defeating Farage at the next general election.”
Business chief warns against 'summer of drift'
The Confederation of British Industry (CBI) has warned the Government against a “summer of speculation and drift” ahead of an expected leadership challenge.
Rain Newton-Smith, chief executive of the influential business group, said: “The UK cannot afford a summer of speculation and drift while politicians are distracted by internal party dynamics.
“The Government must remain focused on delivery and implementation.
“For strong, stable economic growth you need strong, stable, consistent government.
“Political uncertainty dampens business confidence and investment, impacting job creation, wages and the cost of living.
“Business needs to know that the Government can take big decisions, will deliver on its commitments and is prepared to tackle the rising costs of doing business.”
Manchester mayoral election date confirmed
The election for the new mayor of Greater Manchester will take place on 30 July, the Greater Manchester Combined Authority has confirmed.
The contest was triggered automatically following Andy Burnham's victory in the Makerfield by-election.