Andy Burnham has won a parliamentary by-election in Manchester in the United Kingdom (UK), paving the way for him to challenge British Prime Minister Keir Starmer for leadership of the Labour Party, and potentially the country.

Burnham, who is currently the mayor of Manchester, won the by-election yesterday with 55% of the vote, a nearly ten-point increase on what Labour won in the constituency in the 2024 general election.

Reform UK, Nigel Farage’s right-wing populist party, came second, with 35% of the vote, a slight increase on what it won in the general election.

A new hard-right party, Restore Britain, came third, with 7%.

The Conservatives, traditionally one of the UK’s main parties, won only 2% of the vote, a decline of about eight points compared to 2024.

The stage is now set for Burnham to challenge Keir Starmer for leadership of the Labour Party. Only members of parliament (MPs) can be leaders of the Labour Party, which meant that this win was vital for Burnham’s ambitions to succeed the unpopular Starmer.

Burnham will now need the support of 20% of the Labour Party’s parliamentary caucus (81 MPs) to challenge Starmer. If Burnham is successful in getting that level of support and Starmer doesn’t resign and chooses to fight for his position, the vote for party leader will then be chosen by a ballot of ordinary party members.

Burnham is seen as a frontrunner to succeed Starmer, with a number of other Labour Party figures, including a former Cabinet minister, Wes Streeting, and a former deputy prime minister, Angela Rayner, also seen as potential leadership candidates.

If Burnham succeeds Starmer he will be under pressure to call an early general election. Polls show Labour currently trailing in the polls to Reform UK, which means Burnham, if he does become prime minister, may be reluctant to call an early election.

The next election could signal a new era of British politics, with the two parties that have dominated politics in the country for the past century, Labour and the Conservatives, being challenged strongly by parties such as Reform UK and the Greens.