Starmer challenger Andy Burnham sworn in as UK lawmaker

Burnham, 56, arrived in London on Monday and was sworn in as a member of Parliament after nearly a decade away, during which he was the popular mayor of Greater Manchester.

Shortly after Starmer's statement, Burnham said he would run for Labour leader.

He said Starmer's decision to step down "marks the beginning of a transition and it is important that this process is conducted in an orderly and responsible way."

"The country expects stability, seriousness and a continued focus on the issues that matter most and that is what it will get," Burnham said.

Starmer said he would stay in post as prime minister until his successor is in place and that Labour's national executive committee will open nominations on July 9.

Should Burnham be the only candidate, then he could be confirmed as party leader a week or so later. However, if there is a contest, then the election would likely drag on into September.

Burnham has won the support of Wes Streeting, who quit as health secretary last month and had previously indicated he would throw his hat in the ring. Streeting said he would back Burnham for the Labour leadership, saying "he can win the fight of our lives against the forces of nationalism," a reference to the anti-immigration Reform UK party, led by Nigel Farage, that has overtaken Labour in the opinion polls since the July 2024 general election.

"We could spend the summer exaggerating small differences, or we can roll up our sleeves and help him to deliver the change our party and our country needs," he said.

Other potential candidates have yet to comment on Starmer's announcement. They include Starmer's former deputy, Angela Rayner, who resigned last September over an unpaid property tax, and Al Carns, who quit last week as the armed forces minister over Starmer's funding plans for national defense.

There are many in Labour's ranks who say it would be best if no one stood against Burnham so he could enter 10 Downing Street this summer before the party conference. Burnham was tight-lipped on whether he'd prefer a coronation rather than a contest when heading for his train south to London from Manchester.

To join the contest, candidates must win the support of a fifth, or 81, of the party's House of Commons lawmakers.