Andy Burnham made two major U-turns within hours yesterday, amid growing concern his Left-wing agenda will wreck the economy.

In a major climbdown, Mr Burnham said he was no longer pushing for Britain to go back into the EU, just months after declaring: 'I want to rejoin'.

Hours later, in a second reverse, his officials claimed he would now stick to borrowing rules introduced by Rachel Reeves, suggesting his high-spending agenda will have to be funded by tax rises. 

It came after financial markets took fright at signals Mr Burnham would go on a borrowing binge.

Tory Shadow Chancellor Sir Mel Stride said Mr Burnham was 'already costing us all money', with the higher borrowing rates of recent days forecast – should they continue – to cost every family almost £300. 

Reform UK accused Mr Burnham of 'panicking' about a potential backlash to his pro-EU views in the Leave-voting Makerfield constituency, where he is set to fight a by-election to return to Westminster and challenge Keir Starmer.

Reform deputy leader Richard Tice branded the mayor of Greater Manchester the 'King of the U-turn'.

He added: 'He now says he respects the referendum and doesn't want to rejoin the EU. Last year he said he wanted to rejoin the EU. Will the real Andy Burnham please stand up?'

The double reverse came as:

• Sir Keir insisted he would fight the next election as Labour leader, saying he would take on any challenger;
• Deputy PM David Lammy warned that Labour would be 'out of government' unless its MPs halted their 'internecine warfare';
• A YouGov poll of Labour members found that Mr Burnham would beat
• Sir Keir in a leadership contest by a margin of 59:37 – but it dealt a blow to Wes Streeting's chances;
• Mr Burnham hinted at wealth redistribution, nationalisation and price controls as he set out a Left-wing agenda;
• Kemi Badenoch was urged to help 'unite the Right' by standing down the Tory candidate in Makerfield to maximise the chances of Reform defeating Mr Burnham;
• Red Wall MPs warned against embracing the EU, with one saying voters would think Labour MPs were 'off our rockers' to consider rejoining.

Mr Burnham used a speech at the Great North Investment Summit in Leeds to launch a thinly veiled attack on Sir Keir – and sketch out a rival agenda.

He said next month's contest in Makerfield would be 'a by-election like no other', adding: 'A vote for me will be a vote to change Labour. Because Labour needs to change if we are to regain people's trust.'

Trying to appeal to the Left-wing Labour activists who will determine any leadership contest, he denounced the Thatcherite revolution which transformed Britain's future in the 1980s.

He said 'forty years of trickle-down economics' had 'siphoned wealth out of' working communities and 'into the hands of people for whom life was already very good'. 

And he said the impact had been 'compounded' by the wave of privatisations, which Labour has largely left untouched.

However, he played down his long-held opposition to Brexit amid jitters that it could harm his chances in Makerfield, where 65 per cent of locals voted to leave the EU a decade ago.

Allies of Mr Burnham accused leadership rival Mr Streeting of trying to damage his by-election chances by reviving Labour's debate about Brexit.

Mr Streeting described the decision to leave the EU as a 'catastrophic mistake' and said he would campaign to rejoin after the next election. 

Labour sources said Mr Streeting will continue to press the case for rejoining in the coming weeks, as the idea is backed by almost nine out of ten Labour members.

Speaking at the Labour Party conference last September, Mr Burnham said he wanted to rejoin the EU, adding: 'Long term, I'll be honest, I'm going to say it, I want to rejoin.'

But yesterday he reversed his position, saying he 'respected' the referendum result.

'My view is that Brexit has been damaging, but I also believe the last thing we should do right now is re-run those arguments.

'I am not proposing that the UK considers rejoining the EU.'

Lib Dem Europe spokesman Al Pinkerton said Mr Burnham had 'already started U-turning before he's even been elected'.

Dan Carden, chairman of the Blue Labour group of MPs, warned the party against dismissing the referendum vote.

'Working-class communities don't want to be told they got Brexit wrong,' he said. 'They were sending a message, and Labour still hasn't properly heard it.'

Pendle and Clitheroe MP Jonathan Hinder said voters will think MPs were 'off our rockers' if they propose rejoining the EU.

Last year Mr Burnham said Labour had to 'get beyond this thing of being in hock to the bond markets', raising fears he is planning a massive borrowing binge. 

But last night, officials insisted he would stand by the fiscal rules set out by Chancellor Ms Reeves to avoid further spooking the financial markets.