Fears of a Brexit betrayal were mounting last night after Labour's two main leadership hopefuls called for Britain to rejoin the EU.

Andy Burnham and Wes Streeting – the frontrunners to take over from Keir Starmer – said Britain's future was as part of the bloc.

The comments prompted a fiery rebuke from Tory leader Kemi Badenoch, who warned rejoining would be a 'disaster' and plunge the country back into the bitter chaos of Brexit wars. 

Last night Lord Gove – one of the architects of Brexit – said any moves to rejoin would be a 'betrayal', and Reform leader Nigel Farage vowed to make the issue the focus of the Makerfield by-election.

The comments by the leading contenders to become the next Prime Minister suggest they would seek a mandate to rejoin the EU. 

Even Cabinet minister Lisa Nandy said it was clear that no lessons had been learned from Labour's worst local elections defeat in history.

Last year, Greater Manchester mayor Mr Burnham said he wanted to see Britain rejoin the EU 'in my lifetime'. 

Over the weekend, he repeated that there was a case for rejoining 'in the long term' – but tried to downplay his position as he gears up to fight a by-election in a Leave-voting area.

On Saturday, Mr Streeting set out his stall as he said Brexit had been a 'catastrophic mistake'.

'We need a new special relationship with the EU, because Britain's future lies with Europe – and one day back in the European Union,' he said.

But Mrs Badenoch said renegotiating Brexit would be a 'disaster' for the country.

The Tory leader told the Daily Mail: 'What we see before us is a timid and tired Labour Party, exhausted after less than two years in government. Does anyone believe these clowns can negotiate with the EU?

'They're terrified of making any difficult decisions and will only end up giving away power and money just like they did with their terrible Chagos deal and the failed one-in, one-out deal with France.'

She added: 'It will be a disaster for the country and they will reap the whirlwind if they plunge us back into the Brexit wars, ignoring the clear message the country sent in the referendum of 2016 and the elections of 2017 and 2019 – Get Brexit Done.'

She also said Labour should call a general election if a new leader broke the party's manifesto commitments and advocated rejoining the EU.

Writing for the Mail, Lord Gove said: 'The drive towards rejoining is not just acceleration into an economic cul-de-sac, it is also a betrayal of the democratic vote which politicians promised would be honoured and respected.

'After the agonies of the 2017-19 parliament when establishment voices tried to overturn the clear instruction from the people, it would only further undermine people's belief that those who govern us respect our instincts.'

He said Britain should instead make the most of Brexit freedoms in areas where it had a competitive advantage, such as financial services, gene editing, AI and tech.

Mr Streeting's comments also prompted fury from fellow Labour MPs, with Ms Nandy accusing him of restarting the Brexit wars. 'I don't really understand why the sudden focus on Europe,' the Culture Secretary told Sky News.

'If rejoining the EU is the answer, then essentially what we're saying to people is "life was fine in 2015, we just need to go back there". I know Wes is coming up to campaign in the by-election quite soon.

'He will hear loud and clear from people in places like Wigan, Ashton, Winstanley, across Makerfield, that that is absolutely not the case. And the answer has to be bigger.'

She said his argument was a 'bit odd' and the Government was instead taking a 'pragmatic approach' by bringing the UK 'closer to Europe' after a 'poor Brexit deal'.

The timing of Mr Streeting's speech was tricky for Mr Burnham, who is facing a battle with Reform in Makerfield, where two-thirds of voters backed Leave. 

'The Manchester mayor tried to distance himself from the comments over the weekend, arguing that while there is a case for rejoining 'in the long term... I'm not advocating that in this by-election.'

Reform, however, has vowed to make the by-election a de facto Brexit referendum. The party intends to plaster Mr Burnham's views on election leaflets during the contest and brand him 'open borders Burnham'.

Mr Farage told the Mail: 'It's obvious Andy Burnham wants to say one thing to Labour voters in Makerfield while telling Labour MPs something entirely different as he positions himself for power.

'Reform will ensure the voters know exactly where Burnham stands on rejoining the EU.'

Reform won every council ward in the Makerfield constituency in the local elections, securing around half the vote, while Labour won a little more than a quarter.

Other Labour MPs have criticised the calls to rejoin the EU, saying their colleagues should 'stop whining' about Brexit.

Dan Carden, of the Blue Labour group, told the Sunday Telegraph: 'It would be far better to focus government resources on making the most of our sovereign freedoms in trade and defence and foreign policy and start talking confidently about Britain's place in the world, and stop whining about Brexit.' 

Jon Trickett said Labour 'needs to honour the democratic decision', while Lord Glasman said 'national sovereignty is key to the restoration of our national pride'.