Burnham’s by-election win is trouble for PM Starmer

Greater Manchester mayor Andy Burnham won the Makerfield by-election with 55% of the vote, a nearly 9,000 vote margin over the Reform candidate. Burnham has stated that he’d enter any leadership contest for the Labor Party if it’s called. The (now) former mayor is a far more popular figure with the British public, and Labor Party members, than the current prime minister Kier Starmer.

The by-election was triggered when member of parliament (MP) Josh Simons resigned on May 18th with the express intention of letting Burnham run to fill the seat. Under the Labour Party bylaws, only sitting MPs can challenge for the party’s leadership. Since Labour is the majority party in parliament the party’s leader is the UK’s prime minister, which means that any successful challenge for the leadership will result in a new prime minister.

This is the first time since 1965 that a by-election is held because a MP resigned to provide a vacancy for a politician not currently in parliament.

Makerfield isn’t the first by-election that Burnham has tried to run in. Earlier this year, Starmer loyalist denied the (then) mayor a chance to run in the Gorton and Denton by-election; a decision that resulted in a victory for the Green Party’s candidate Hannah Spencer, and the first time that the Greens had ever won a by-election in the United Kingdom. Starmer’s loyalist were able to bar Burnham from running in the Gorton and Denton by-election because there is no American-style primary process in Britain; candidates are decided by a committee within the party made up of its registered members.

Labour’s selection committee learned its lesson because Burnham was allowed to stand as its candidate in Makerfield which makes him one of three MPs that have stated they will challenge Starmer for the party’s leadership if a leadership contest is declared. Burnham, or one of the other MPs, would need support from 20% of their fellow Labour MPs (81) in order to initiate a contest. Once the party confirms a leadership contest, its affiliate and registered members would vote by mail; all it would take to unseat the PM is a simple 50% of the vote.

Starmer has faced calls for his resignation, along with multiple resignations from his cabinet over the last year. Those calls grew worse after Labour suffered humiliating losses in council election across the country in local on May 1st, 2026. It was those losses that helped drive Simons to step down from his seat which caused the Makerfield by-election.