Keir Starmer will have to quit even if Andy Burnham loses the Makerfield by-election and fails to secure a House of Commons seat, a senior Labour MP has claimed.Jess Phillips, who recently resigned as a Government minister, said she believes there will be a leadership battle regardless of whether Mr Burnham returns as an MP or not.Mr Burnham, the Greater Manchester mayor, is standing in the Makerfield contest with a view to going on to challenge the Prime Minister.But Ms Phillips - an ally of rival leadership hopeful Wes Streeting - claimed there would be a change in Downing Street even if Mr Burnham doesn't succeed in his bid to return to Westminster.Speaking at the Hay Festival on Monday, she said: 'I think even if Andy Burnham doesn't win in Makerfield there will be a change of the Prime Minister.'The Makerfield by-election is being fiercely contested with all the other main parties standing candidates against Labour's Mr Burnham.Reform UK is eyeing another by-election success in a Northern seat following its success in Runcorn and Helsby last year.But party leader Nigel Farage has warned about a schism in the Right-wing vote after controversial billionaire Elon Musk backed rival group Restore Britain. Jess Phillips, who recently resigned as a Government minister, said she believes there will be a leadership battle regardless of whether Andy Burnham returns as an MP or not Mr Burnham, the Greater Manchester mayor, is standing in the Makerfield contest with a view to going on to challenge the Prime Minister Ms Phillips said she felt 'liberated' since resigning as safeguarding minister with a scathing letter accusing Sir Keir of failing to be 'bold'.'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,' she said.'But then also what he has not done is grab that particular mantle or even actually tell the story.'I think even if Andy Burnham doesn't win in Makerfield there will be a change of the Prime Minister,' Ms Phillips added of the Greater Manchester by-election.'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 PM changes.'Ms Phillips quit her Home Office role earlier this month, joining a string of ministers resigning in protest at Sir Keir's leadership.She accused him in her letter 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'.