Andy Burnham wins Makerfield by-election, triggering Starmer resignation and Labour leadership race

By-election victory and the right-wing split

Andy Burnham won the Makerfield seat on 18 June, securing a return to Westminster and the platform to challenge for the leadership. His path was eased by a fractured right-wing vote, with Nigel Farage's Reform UK and Rupert Lowe's splinter Restore Britain dividing the populist electorate. The seat is a Labour stronghold that had been won by 13 points in 2024, but Reform had hoped to mount a serious challenge. Instead, Restore Britain's presence, averaging 7–8% in constituency polling, undermined Reform, and the Conservatives ultimately pushed Reform into third place. Peter Thompson, a local record-shop owner, captured the sentiment:

“All my voting in life there's only been two parties that have run this country, Labour and Conservatives. Look around you, it's a mess.”

Burnham has been dubbed the "Reform slayer" for seeing off the populist threat.

Starmer resigns and leadership contest begins

On 22 June, Prime Minister Keir Starmer announced his resignation as Labour leader and prime minister, days after Burnham's victory. Starmer told reporters he did not think a challenge was good for the country but that he would defend his record:

“If there is a contest... then yes I will run, I will stand.”

A POLITICO poll found that only one in five UK adults wanted Burnham installed immediately; a 54% majority preferred a full leadership contest, including 57% of Labour voters. The contest will determine who leads the party into the next general election.

Immediate elevation20%

Leadership contest54%

Undecided/other26%

Immediate elevation

20 %

Leadership contest

54 %

Undecided/other

26 %

Data from the article text

Fiscal constraints and market warnings

A Burnham-led government would inherit tight fiscal headroom. Bond investors have warned his ambitions, including possible nationalisation of utilities and a council housebuilding programme, could clash with market realities. Mark Dowding, chief investment officer at RBC BlueBay, said:

“He is boxed in by the fact that government finances are in a weak position, and if he chooses to ignore this reality, then he could find himself under pressure very quickly.”

Burnham has committed to Rachel Reeves's fiscal rules and ruled out rises in income tax, VAT or national insurance, limiting his options. Andrew Goodwin, chief UK economist at Oxford Economics, added:

“Anywhere he wants to spend more, he's going to have to either cut spending elsewhere to finance it, or he's going to have to increase taxes.”

Jim O'Neill, a former Goldman Sachs economist and adviser, has called for billions more in borrowing to fund infrastructure.

Building a Downing Street team

If Burnham wins the leadership, he is expected to replace Rachel Reeves as chancellor, offering her a more junior cabinet role. A close ally told the BBC: "Andy really respects Rachel and I'm confident he'll want her in his top team." James Purnell, a former minister under Gordon Brown, would become Downing Street chief of staff. On defence, Burnham has begun talks with John Healey, who resigned as defence secretary earlier this month warning that planned military spending increases fall "well short of what is required".

Economic headwinds and political reality

The UK's real output per head in 2025 was 27% smaller than if the 1970–2007 trend had continued. Productivity growth has been sluggish, investment rates are the lowest in the G7, and an ageing population is adding to fiscal strains. A change of Labour leadership may not easily overcome these obstacles; commentators note that UK politics is hostile to making tough choices, with many voters having given up on hope after two decades of disappointment. Burnham has acknowledged the bond-market constraint, having earlier said the UK was "in hock" to the markets, a stance he has since moderated.