Andy Burnham vowed a 'new path for Britain' today as he looks increasingly certain to storm Downing Street after a stunning win in Makerfield.The outgoing Greater Manchester Mayor secured a majority of 9,000 votes over Reform in a by-election result that sparked tears of joy from Labour Left-wingers - who want far more extreme tax and spend policies.Mr Burnham made clear at a rally in Ashton this morning that he will try to replace Keir Starmer, 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.' He fled after delivering the stump speech, ignoring questions shouted by reporters. 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, while one frontbencher predicted Cabinet resignations from the start of next week unless he agrees to go.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. Tensions have been so great that the pair have not been in touch since he was selected as Makerfield candidate. 'If there is a contest, then yes, I will stand,' Sir Keir said. 'I have said repeatedly, I am not going to walk away from that.'In a lunchtime call with Labour staffers, the premier appeared to claim credit for the by-election result, saying the 'tide is turning' on Reform in the national polls. 'Let's pull together as a party and a movement,' he said. 'The one thing we've got to avoid doing is plunging our party and our country into chaos by turning on each other and tearing apart our party and our movement. That has never worked. That's what the last government did. We need to learn that lesson.'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.' On a potentially pivotal day for Britain's future: Interest rates on Government debt ticked up slightly this morning, although similar moves have been seen in other European bond markets amid uncertainty over oil prices; The danger of a lurch to the Left was underlined as official figures showed public sector borrowing surging to a record level for May, outside of the Covid peak. Interest rates on the country's debt mountain and the Government's spending splurge were behind the spike;In a separate by-election contest in Aberdeen South, the Tories secured a huge win over the SNP after successfully turning the race into a referendum on oil and gas drilling in the North Sea;The SNP did hold Arbroath and Broughty Ferry in a third by-election result of the night;A by-election to replace Mr Burnham as Greater Manchester Mayor is due to be held on July 30, with Labour's chances boosted by the Government changing the electoral system. Andy Burnham 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'Keir Starmer was on a housing-related visit in London with his deputy David Lammy today as he faces calls to agree an 'orderly and managed' transition of power