Greater Manchester Mayor Andy Burnham said Thursday that he would seek to enter any Labour leadership contest if voters elect him to Parliament in the Makerfield by-election on 18 June, placing himself alongside former Health Secretary Wes Streeting as a potential challenger to Prime Minister Sir Keir Starmer.

“I can’t do anything unless I’m lucky enough to get the support of people here,” Burnham told BBC Question Time from the constituency. “But if I get your support, I would seek to represent you at the highest possible level and give this constituency maximum power and influence.”

Pressed on his ambitions, Burnham added: “I think Wes Streeting seems to have launched a leadership contest, so if that is running I would seek to join it, but I’d have to persuade members of the Parliamentary Labour Party to do the same.”

Any challenger seeking to trigger a leadership contest must be an MP and secure the backing of 81 Labour MPs. Streeting, who resigned as Health Secretary last month and called on Starmer to step aside, has confirmed he would enter any potential contest and encouraged voters to back Burnham in Makerfield, saying he wants a “proper contest with the best candidates on the field.”

The by-election was called after then-Labour MP Josh Simons stepped down, a move he said was to allow Burnham to run for Parliament and potentially mount a leadership bid. Burnham served as an MP from 2001 to 2017 before being elected Greater Manchester Mayor. He has previously pledged to serve his current term as mayor through 2028.

Starmer has defied calls from some Labour MPs to resign after the party suffered heavy losses to Reform UK in local elections last month. No formal leadership challenge has been launched against him. The prime minister said he would not “walk away” from Downing Street despite ministerial resignations, most notably from Streeting.

Reform UK candidate Robert Kenyon, a plumber and local councillor, used his appearance on the same Question Time episode to attack Burnham’s record.

“We need to get normal people in politics, people who care about the place, people who live in the place and people who want to stay here and not use it as a stepping stone for other things,” Kenyon said. He criticized Burnham’s time as mayor, saying that while Manchester “thrives we’re struggling to survive in Wigan” and that “we’ve been left behind.”

Conservative candidate Michael Winstanley questioned why Burnham was seeking a return to Parliament after previously pledging to serve his current term as mayor, adding he was “disgusted” and “sad that we’re having this by-election foisted upon us.”

“We will get rid of Keir Starmer whichever politician is elected in this by-election and if you vote for me, it’ll speed it up straightaway,” Winstanley said.

Burnham responded by saying “you cannot control events in politics” and highlighted Labour’s losses to Reform in recent council elections in the area.

Green Party candidate Sarah Wakefield called for “serious conversations about who is contributing for a better future for our children, to solve the climate crisis, to get our high streets going, to make sure that we have the money back in towns and villages.”

Liberal Democrat candidate Jake Austin described the by-election as an “election for a potential future prime minister via the backdoor and that’s not the right way to be doing politics.”

Burnham and Kenyon were among five of the 14 candidates in the by-election who appeared on Question Time. The remaining candidates were not represented on the program.