Exclusive: Labour MP Rosie Duffield joins a growing number of MPs calling for the party to join a Remain alliance at the next general election.

An increasing number of Labour MPs want the party to form a Remain alliance at the next election.

Labour has rejected working together with other opposition parties when the UK next goes to the polls.

However, around 20 Labour MPs believe the party should stand aside for the Lib Dems, Greens, and other pro-European Union parties in some seats at the next election.

Labour MP Rosie Duffield told Business Insider that an electoral pact would be the "only way we're going to prevent Boris Johnson and his cabal of Brexit zealots securing a majority at the next election."

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Jeremy Corbyn is coming under pressure from a growing number of Labour members of Parliament to stand candidates down in certain seats as part of an anti-Brexit pact with other pro-European parties at the next election.

Anti-Brexit campaigners are currently talking to the Liberal Democrats, Green Party, and other pro-Remain opposition parties, about them working together in a number of seats at the next general election, with the aim of removing Boris Johnson from power and creating a majority for holding a new referendum.

This would involve parties standing aside for each other in certain constituencies, in order to maximise the chances of pro-Remain candidates winning. Those leading the talks hope the Labour Party can be convinced to participate.

Sources involved in efforts to build a Remain alliance say around twenty Labour MPs privately support the idea.

At Labour's conference in Brighton last week, shadow Treasury minister MP Clive Lewis became the first to publicly back a Remain alliance, saying that standing aside for anti-Brexit candidates was a "no-brainer."

"At present it's the central Labour party that decides that a candidate will be stood in every single constituency, it's part of our constitution," the Labour MP for Norwich South told party members.

He added: "[But] I think we should trust in our local Labour members to know what's happening on the ground to be able to make a decision about whether they want to stand a candidate."

Now another Labour MP, Rosie Duffield, has joined the call for the party to work as part of a pro-European alliance.

Speaking exclusively to Business Insider, she said: "Labour shouldn't be scared of electoral pacts with parties who want to stop Brexit.

"It's a given that Labour will have to stand aside in some seats to let the other progressive parties claim a victory.

She added: "That's the only way we're going to prevent Boris Johnson and his cabal of Brexit zealots securing a majority at the next election — by working together.

"Our party will never be forgiven if we put petty tribalism ahead of the national interest."

Anti-Brexit activists believe only an electoral pact will stop Johnson

Rosie Duffield MP. Nicola Tree/Getty Images

Both Lewis and Duffield are supporters of the Best For Britain campaign to stay in the EU.

Best For Britain analysis suggests there are 158 constituencies — around a quarter of House of Commons seats — where pro-EU parties working together could feasibly keep out Conservative candidates.

Speaking at Labour conference last week, Lewis pointed out that a Remain alliance would almost certainly have prevented Conservative MP Zac Goldsmith from winning in Richmond Park at the last election in 2017, for example.

Best For Britain believes that with Prime Minister Johnson leading in the opinion polls, and Nigel Farage's Brexit Party set to stand aside for hard Brexiteer Conservative candidates at the next election, a pact involving opposition parties including Labour will likely be the only way of preventing a Johnson victory.

The group has identified 158 seats in its analysis, where smaller parties would need to step aside for Labour in 110 of them to stop the pro-EU vote splintering. In the rest, Labour would have to back a smaller opposition party.

The Labour leadership is currently opposed to working together with other parties at the next election.

Shadow Foreign Secretary Emily Thornberry last week told Business Insider she was wholly against it.

Furthermore, while a majority of Labour members and MPs support remaining in the EU, and Labour policy is to hold a new referendum, the party is not yet committed to campaigning for Remain in a new public vote.

Corbyn has said that as prime minister, he would negotiate a new Brexit deal, and then let party members decide whether party policy should be to go ahead with Brexit under the terms of that deal, or stay in the EU.