A stalwart of the Labour Left welled up today as he hailed Andy Burnham's by-election win as a chance to 'redistribute wealth'.

John McDonnell - who served as shadow chancellor under Jeremy Corbyn - became tearful on LBC as he watched footage of Mr Burnham's victory speech in Makerfield.

Asked if he was 'emotional', Mr McDonnell said: 'I certainly am.'

The Hayes & Harlington MP said he was 'lifted' by the result, arguing it showed Reform can be 'trounced'. 

Pressed what would change with Mr Burnham as PM, Mr McDonnell said: 'For me... it opens up a space to have a proper debate and discussion while we are in government.

'On the fiscal rules I think if you look at some of the advisers he has now put around him... 

'I think there is a creative way of looking at those fiscal rules so we can actually ensure that we can invest on the level that we need to, but also look at the redistribution of wealth and income in this country so that we can tackle the levels of poverty that we have got.'

Mr McDonnell said Sir Keir should act out of 'comradeship' and 'put the party and the country beyond his own career'.

He suggested a leadership contest would be pointless, saying Blairite favourite Wes Streeting putting his name forward would be an 'infantile self-promotion exercise'. 

Mr McDonnell said a handover of No10 was 'inevitable'. 'I think the general view is that let's try and find a way through this in which Keir can stand down with a bit of dignity and then as a result of that Andy takes over,' he said. 

Mr Burnham secured a majority of 9,000 votes over Reform in a contest that most expected to be far closer.

The new MP made clear at a rally in Ashton this morning that he will try to replace the PM, calling for 'real change', 're-industrialisation' and an end to 'trickle down economics'. 'It is our last chance to change but we are going to take it... we are going to lay out a new path for Britain.' 

The scale of the victory heaps massive pressure on Sir Keir to allow a 'coronation' that could happen within days. Even previously loyal MPs are calling on him to make way for his rival.

But the premier showed no signs of budging as he toured a housing development this morning, saying he 'will stand' in any leadership contest and will not 'walk away'. He revealed he has not yet spoken to Mr Burnham directly. 

'If there is a contest, then yes, I will stand,' he said. 'I have said repeatedly, I am not going to walk away from that.'

Earlier Sir Keir posted on X congratulating Mr Burnham, but pointedly praising 'Labour's campaign'. 

However, ex-minister Baroness Harman - who was appointed as an adviser by Sir Keir just last month - has called for a 'process' where MPs are given the choice of who is going to be PM. She argued that a woman should also be on the ballot. 

Labour backbenchers who previously supported Sir Keir staying are now saying he needs to quit.

One told the Daily Mail: 'Andy Burnham has exceeded all expectations and I'm absolutely sure that there'll be an orderly transition of leadership now. Keir would be unwise to try and stop it.' 

Nigel Farage admitted he was 'disappointed' by the result, acknowledging Reform had struggled to counter the message of 'vote Burnham, get Starmer out'.

He blamed Restore splitting the Right for Reform getting 16,000 votes instead of the 18,000 he had expected. In a direct message to those who supported Rupert Lowe's outfit, Mr Farage said: 'What do you want? We are the challenger party to the Left in this country.' 

The markets have been spooked by signs that Mr Burnham could take Labour to the Left with a major spending splurge funded by borrowing and even more tax.

He has hinted at wealth taxes, revaluing council tax and called for nationalisations.

But Mr Burnham has also executed screeching U-turns on a slew of ideas, including ruling out billions of pounds of compensation for so-called WASPI women just hours after supporting the prospect. 

The former Cabinet minister caused a furore at last year's Labour conference in Liverpool after suggesting in an interview that politicians had to 'get beyond this thing of being in hock to the bond markets'.

But he later seemed to row back from those comments, saying last month he supported Ms Reeves's fiscal rules.

He told ITV: 'There needs to be a plan to get debt down, but beyond that, we need to change politics and take the turbulence out of British politics, because that is a cause of uncertainty that then has that impact in the markets.'

Rachel Reeves, who is regarded as unlikely to be kept on as Chancellor if Mr Burnham becomes PM, delivered a shot across his bows yesterday, warning the fiscal rules must stay in place.

She told a conference: 'We got elected on the promise to return stability to the economy, and anyone who wanted to deviate from that will not be fulfilling the manifesto commitments.'