Labour would overtake Reform if Andy Burnham replaced Sir Keir Starmer as Prime Minister, damning new polling has revealed.

A survey conducted by polling gurus at More in Common suggested that Labour would scoop 30 per cent of the vote if the Greater Manchester Mayor succeeded Sir Keir.

The figure is up five points compared to the total amassed by the Prime Minister, with Reform UK remaining unchanged in both scenarios on 28 per cent.

Meanwhile, the Tories would drop two points to 18 per cent if Mr Burnham replaced Sir Keir and the Liberal Democrats would register a one-point drop to 12 per cent.

The Green Party, which is now being led by firebrand environmentalist Zack Polanski, would drop from eight to six per cent, More in Common found.

Such a shift could completely alter Labour’s electoral fortunes.

With Sir Keir at the helm, Reform UK runs out as clear frontrunners, scooping up 294 seats under Electoral Calculus’s predictor model.

Despite losing a wealth of experienced Tories, a Conservative rump of 61 seats could prove enough to elect a right-wing coalition.

Meanwhile, Labour would suffer its worst electoral defeat since 1935, ending up on just 192 seats.

The Liberal Democrats would lose 21 seats to take them down to 51.

However, under More in Common’s hypothetical polling on Mr Burnham, Labour would fall just 29 seats short of a majority of 297 seats.

Reform UK would trail in a close second on 225, up from just five seats in the 2024 General Election.

The Tories would secure just 50 seats, narrowly avoiding being overtaken by the Liberal Democrats on 44 seats.

Despite the polling boost for Mr Burnham, Sir Keir appeared to dismiss the threat posed by the Greater Manchester Mayor.

The Prime Minister said: “I do want to be really clear about our fiscal rules, because economic stability is the foundation stone of this Government.

“It was three years ago this week that Liz Truss showed what happens if you abandon fiscal rules. In her case, she did that for tax cuts, but the same would happen if it was spending.

“And we saw what happened to working people three years ago, the infliction of harm on them.”

Mr Burnham has not ruled out a return to Westminster and set out his own mini-manifesto in an interview with The New Statesman.

The ex-Leigh MP also claimed that Labour MPs had contacted him over the summer about a potential tilt for the top job.

However, Reform UK insiders believe that Mr Burnham will face an uphill struggle to win a by-election.

“Burnham faces the same dilemma as Boris,” Reform UK’s policy chief Zia Yusuf said. “There’s no seat he’d be assured of winning in pursuit of the leadership.

“He’d be up against a Reform campaign machine that’s even stronger now than it was in Runcorn & Helsby when we won a ‘safe’ Labour seat. Does he have the stones?”

Mr Burnham would need to resign as Greater Manchester Mayor, win a Westminster seat in a by-election, and receive at least 80 nominations from Labour MPs.

The door seemed to shut on Mr Burnham’s rumoured bid after two Greater Manchester MPs ended speculation that they could trigger by-elections.

Gorton & Denton MP Andrew Gwynne and Blackley & Middleton South MP Graham Stringer both instead committed to representing their Manchester constituents in Westminster.