Andy Burnham failed to suppress a grin last night as a member of the Question Time audience tore into his Labour civil war foe Keir Starmer, saying: 'Everybody wants him to go, we can't stand him.'The Greater Manchester mayor smiled as the woman said she wanted him to win the Makerfield by-election so he could oust Sir Keir, adding: 'The sooner the better.'Minutes later Mr Burnham used the BBC TV special ahead of the vote in the Wigan seat to confirm he would seek to replace Sir Keir in No10 if he is elected on June 18.His confirmation that he has designs on national power came at the same time as a new poll showed he has a ten-point lead over Reform's Robert Kenyon in Makerfield.If the so-called 'King of the North' wins the Westminster seat it will fire the start gun on a summer of bitter Labour infighting, with allies of Sir Keir vowing he will not step aside meekly but will take on Mr Burnham and other challengers like Wes Streeting. On Question Time last night, presenter Fiona Bruce introduced the audience member as 'the woman here in the jacket' before the voter said she backed Mr Burnham.The woman went on: 'The sooner the better that Keir Starmer walks out of Downing Street, the better for me and everybody else. We want him to go. Everybody wants him to go, we can't stand him actually. But he's not for the people anyway.'Bruce interjected, joking 'say what you really think', prompting a big smile from Mr Burnham who wrote something down on his notepad. The woman then continued: 'Well, yeah. He's not for the people, he doesn't listen, that's his downfall.' A Question Time audience member says of Sir Keir Starmer: 'Everybody wants him to go'Andy Burnham smiles after Fiona Bruce's interjection following the woman's comments Presenter Fiona Bruce had joked that the woman should 'just say what you really think'But Sir Keir's allies today warned of a tough summer for the party, with Deputy Prime Minister David Lammy telling LBC: 'There is no contest at the moment, and my view is it would be a huge distraction at this time.'The Prime Minister ... has been absolutely clear: if there is a contest, he'll be in it.' And Attorney General Lord Hermer told the BBC: 'Keir has constantly been underestimated. I imagine through his life he has been underestimated. He has always proven his critics wrong. No one has ever got rich betting against Keir Starmer.'The vote in the by-election is expected to be a race between Mr Burnham and Reform UK's candidate Mr Kenyon, a plumber and local councillor.During Question Time, the woman asked in a question to Mr Benham: 'But what my question is, Reform have in the manifesto, they're going to raise the tax threshold. Why is that not in your manifesto?'Because if you put that in your manifesto, you'll walk this by election, easy. You need to put that in your... it's not for everybody, for pensioners.'Bruce said following the woman's question: 'Just so you're aware, Robert may say this, in terms of raising the tax threshold, I think it was to £20,000.'That was a Reform policy, it's not currently a Reform policy. It's an aim, isn't it, but not a current policy?'The woman said: 'It is in your manifesto' - but Bruce clarified: 'It is no longer.'Mr Kenyon then said: 'It was in 2024, but I mentioned pensioners are getting poorer. Just think about what happened with the winter fuel allowance, that got taken off all the pensioners.'The programme then heard from Jake Austin from the Lib Dems and Sarah Wakefield of the Green Party, before Mr Burnham confirmed in response to another question that he would challenge Sir Keir for the Labour leadership if he wins the by-election.Mr Burnham, who is widely viewed as Sir Keir's main rival for the top job if he wins, said he had asked his team to help 'develop a policy' but will need the backing of the Parliamentary Labour Party.'I'm not somebody who gets ahead of myself. I can't do anything unless I'm lucky enough to get the support of people here,' he explained.'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.