Former Greater Manchester Mayor Andy Burnham said he will join a Labour leadership contest to succeed outgoing party leader and British Prime Minister Keir Starmer, who announced his resignation on Monday.

Starmer said he will stay on as prime minister until his successor is chosen.

“Keir has given huge service to our country and I want to thank him for his leadership and dedication during such a challenging period. His decision marks the beginning of a transition and it is important that this process is conducted in an orderly and responsible way. I will put myself forward as part of this process,” Burnham wrote on X, formerly Twitter.

“The country expects stability, seriousness and a continued focus on the issues that matter most and that is what it will get,” he added.

Burnham is the clear favorite to succeed Starmer after defeating a Reform UK candidate in a special election in Makerfield last week.

Wes Streeting, who recently resigned as U.K. health minister and had previously said he would join a potential leadership contest, declared he is throwing his support behind Burnham.

“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. That is the choice that I am making and I hope that everyone else will back Andy, too,” Streeting wrote.