Andy Barnum, the Labour Party mayor of Manchester, won the House of Commons by-election in the Makerfield constituency on June 18, 2026 [1, 2].

The victory is seen as a significant blow to Prime Minister Keir Starmer. Barnum has positioned himself as a challenger to the current leadership, capitalizing on voter dissatisfaction and internal party pressure to replace the prime minister.

Barnum secured approximately 25,000 votes [1]. He defeated the Reform UK candidate by a margin of more than 9,000 votes [1]. This result marks Barnum's return to Parliament after nine years [1].

Following the announcement, Barnum addressed the need for systemic change within the government. "Everyone knows that politics is not functioning," Barnum said. "But I want to say to my party: now is the last chance to change" [1].

Observers suggest the result has shifted the internal dynamics of the Labour Party. Reuters said the victory has opened a path to removing Prime Minister Starmer [1].

Barnum, 56, faced a competitive race against Reform UK, but his win reinforces his standing as a potential candidate for the next prime minister [3]. The Makerfield constituency, located in the Midlands of central England, served as a bellwether for the current mood of the electorate [1, 2].

Throughout the campaign, Barnum emphasized that the current administration's failure to address public concerns has left the party vulnerable. He said that the victory in Makerfield is not merely a local win, but a mandate for a different direction for the Labour Party [1].

“"Now is the last chance to change"”

The result in Makerfield transforms Andy Barnum from a regional leader into a national political threat to Keir Starmer. By defeating a Reform UK challenger by a significant margin, Barnum has demonstrated that a more populist or alternative Labour approach can maintain party loyalty while attracting dissatisfied voters. This victory provides the necessary political capital for internal dissidents to formally challenge Starmer's leadership, potentially triggering a leadership contest.