Jess Phillips has said Sir Keir Starmer will likely still be ousted from No 10 even if Andy Burnham is unable to return to parliament to challenge him.
The prime minister has come under immense pressure in recent weeks following the Labour Party’s disastrous results in the local elections.
Nearly 100 of Sir Keir’s own MPs called for him to step down as PM, while multiple ministers – including Ms Phillips and health secretary Wes Streeting – resigned.
A leadership challenge has yet to be officially triggered, with other would-be candidates appearing to wait for the potential return of the mayor of Greater Manchester to parliament.
But despite Mr Burnham being seen as Sir Keir’s most likely successor, Ms Phillips has said a challenge will go ahead regardless of what happens in the Makerfield by-election.
“I think even if Andy Burnham doesn’t win in Makerfield there will be a change of the prime minister,” she told Hay Festival.
“I’ve never been to Wigan in my life, so I have absolutely no idea about the people there, so I shall go and find out. But, yes, I imagine Andy Burnham will win it, and I imagine then that the prime minister changes.”
Ms Phillips stepped down as safeguarding minister earlier this month, joining a string of mostly junior ministers quitting in protest at Sir Keir’s leadership.
In a letter to the PM, she accused him of failing to act fast enough on violence against women and girls, saying his “desire not to have an argument means we rarely make an argument, leaving opportunities for progress stalled and delayed”.
Speaking at the festival, Ms Phillips said she felt “liberated” since her resignation.
She said on Monday: “I can sort of see where Keir Starmer and Keir Starmer’s loyalists come from, in that the idea that we could repair a country so badly broken after years of austerity quite so quickly, is just a lie.
“But then also what he has not done is grab that particular mantle or even actually tell the story.”
The prime minister has vowed to stay on as Labour leader and insisted he will fight any official challenge against him.
But the fallout from the disastrous local election results has exposed deep divisions within the Labour Party, throwing Sir Keir’s government into chaos.
Splits within the cabinet have been on full display, after the health secretary, Wes Streeting, dramatically resigned following days of intense speculation.
Mr Streeting told reporters on Friday that he held off triggering a leadership race to give Mr Burnham time to find a path back into the Commons.
If Mr Burnham wins the Makerfield by-election, he will likely use his return to parliament as an opportunity to trigger a leadership contest against Sir Keir, which polls suggest he would win.
But allies of Mr Burnham have suggested he may not launch a bid for the party leadership immediately if he is successful in the 18 June contest.
