JEREMY Corbyn has been accused of risking electoral “catastrophe” in Labour-supporting Leave seats following his decision to swing the party leadership behind a second EU referendum on Brexit.

And the shift in policy caused an internal spat between members of the Shadow Cabinet and senior aides.

The Labour leader insisted if Theresa May's Brexit deal won parliamentary approval, then “there must be a confirmatory public vote".

Speaking in the Commons, Mr Corbyn said: "The Prime Minister's botched deal provides no certainty or guarantees for the future and was comprehensively rejected by this House.

"We cannot risk our country's industry and people's livelihoods and so if it somehow does pass in some form at a later stage, we believe there must be a confirmatory public vote to see if people feel it is what they voted for."

But in response, Theresa May hit back, saying the Labour leader had broken his promise to respect the 2016 referendum result.

"Anyone who voted Labour at the last election because they thought he would deliver Brexit will rightly be appalled," she declared.

While Labour’s shift in policy won plaudits from Remain-supporting MPs, those representing Leave seats warned of dire electoral consequences for the party.

Nottinghamshire MP John Mann, who voted to leave the EU, said the move would be "catastrophic” to Labour in the Midlands and northern England.

"Voters won't have it. The last person to renege on their manifesto was Nick Clegg; it didn't end very well for him on tuition fees.

"Our manifesto was unambiguous: we would accept the result of the referendum. A second referendum doesn't do that and the voters - in very, very large numbers - will not accept that."

Stoke Central MP Gareth Snell suggested Sir Keir Starmer, the Shadow Brexit Secretary, had engineered the shift in Labour's stance.

"If I was being a bit unkind, part of me thinks this has been what Keir wanted all along, to move the Labour Party to a point of so much confusion this seems to be the only way forward, which is disappointing because in the early days I thought he really wants to speak to those of us in Leave areas, who have real concerns, not just for what this means for our party, but what this means for the connection our party has with those communities."

It has been suggested anywhere between 25 and 50 Labour MPs are opposed to the shift in policy.

Meanwhile, senior shadow Cabinet ministers defended the change of tack amid suggestions senior party sources were briefing against them.

After Monday night’s PLP meeting, at which Mr Corbyn revealed his U-turn, a senior source made clear that in any People’s Vote the choice would not be between Mrs May’s deal and staying in the EU because that would “not be a reasonable choice” given the PM’s proposal had been comprehensively rejected by Parliament.

This appeared to directly contradict a view put forward by Emily Thornberry, the Shadow Foreign Secretary, who made clear the referendum would be on Mrs May’s deal or staying in the EU.

Ms Thornberry tweeted that the suggestion she had misspoken Labour policy was “nonsense,” adding: “For clarity, if Theresa May won’t accept our deal, then the public must decide: do we accept whatever deal she gets through or do we Remain. Got it?”

Later, in another expression of annoyance, Tom Watson, the deputy leader, added: “Whoever briefed that my colleague ‘misspoke’ undermines the sovereignty of the current Shadow Cabinet.”

And Sir Keir stressed that "elected politicians" rather than aides were the ones setting out Labour’s position.