Andy Burnham has launched his bid for the Labour leadership, announcing he will challenge Sir Keir Starmer to become Britain's next prime minister.
The Greater Manchester Mayor is first hoping to use the Makerfield by-election to return to Westminster.
Voters in the northern constituency will go to the polls on June 18 after ex-minister Josh Simons announced he was stepping down as the MP.
Mr Burnham must beat off the challenge of Reform UK, which recorded a clean sweep of wins across the eight wards in last month's local election, registering a total vote share of 50 per cent.
If successful, Mr Burnham will officially launch his leadership bid.
Confirming the bid on BBC Question Time, Mr Burnham said: "I'm not somebody who gets ahead of myself.
"I can't do anything unless I'm lucky enough to get the support of people here.
"But if I get your support, I would seek to represent you at the highest possible level and give this constituency maximum power and influence."
Andy Burnham has launched a bid for the Labour leadership, announcing he will challenge Sir Keir Starmer for No10
|GETTY
He added: "I think Wes Streeting seems to have launched a leadership contest, so if that is running, I would seek to join it.
"But I'd have to persuade members of the Parliamentary Labour Party to do the same. So that's the only question... I've said to my team, let's have a proper look at this and let's develop a policy."
Mr Burnham previously told GB News the Makerfield by-election will be a "turning point for British politics”.
Speaking to Chief Political Correspondent Katherine Forster, Mr Burnham also insisted he "gets it" on immigration and will work to rebuild public trust on the issue.
Sir Keir Starmer has the lowest satisfaction and approval ratings of any serving Prime Minister in British polling history
|GETTY
He said: "I'm standing before the people of Makerfield. I think this is a really necessary moment in British politics.
"I know they'll experience inconvenience over the next four weeks, but I do feel that this by-election could be a turning point for British politics."
The 56-year-old left Westminster after two unsuccessful attempts to win the Labour leadership in 2010 and 2015.
He is expected to face a challenge from former Health Secretary Wes Streeting, who resigned from the Prime Minister's cabinet after the disastrous local elections.
Andy Burnham is expected to face a challenge from former Health Secretary Wes Streeting
| REUTERSMr Burnham is the only major political figure in the country to maintain a positive net favourability rating (+4) among the British public, YouGov polling reveals.
Polls show 34 per cent view him favourably, compared to 30 per cent unfavourably.
This compares to Sir Keir, whose net popularity has plummeted to -46, with 71 per cent viewing him unfavourably.
This is the lowest satisfaction and approval rating of any serving prime minister in British polling history.
Mr Burnham is the only major political figure in the country to maintain a positive net favourability rating
| GETTYA No10 spokesman said: "With Keir Starmer’s leadership, this Labour government is supporting people with the cost of living, cutting NHS waiting lists, restoring control of our borders and lifting half a million children out of poverty.
"The country expects us to focus on governing and to deliver change for hardworking people, not get distracted by Westminster debates.
"The Labour Party has a process for challenging a leader and it has not been triggered.
"The Prime Minister will not walk away from the mandate he was given just two years ago to build a stronger, fairer Britain."
Our Standards: The GB News Editorial Charter