Trade unions split over whether Labour should back Remain in second EU referendum
Labour splits on Brexit have erupted again after the party's biggest union backer warned Jeremy Corbyn not to support staying in the EU.
Howard Beckett, Unite's assistant general secretary, made the union's position clear during talks with the Labour leader on Monday.
It is understood the union’s executive committee agreed on its Brexit position - which also includes opposition to a second referendum - at a meeting on Sunday.
Mr Corbyn, who has called for a referendum on any Brexit deal passed by Parliament, met with the leaders of every trade union affiliated to Labour to canvas their views ahead of a crunch Shadow Cabinet meeting on Tuesday.
CWU general secretary Dave Ward also made clear his union's opposition to Labour campaigning for Remain.
But every other union, including Unison, the GMB and TSSA, urged Mr Corbyn to back staying in the EU.
A trade union source told PoliticsHome: “The CWU are resisting, but not to the same extent as Unite.
"The Bakers’ Union and Aslef have come round to the view that a Remain position is where Labour needs to be.
"The result of the European election has focused a lot of minds. People realise that we need to become a Remain party to win votes back from the Lib Dems."
Senior Labour figures believe the party must make clear its position on Brexit before Parliament breaks up for the summer recess on 25 July.
"This can’t be allowed to drag on over the summer - people need to know where we stand," said one source.
Mr Corbyn is thought to be edging closer to supporting Remain, but some of his closest aides - including chief of staff Karie Murphy and communications chief Seumas Milne - are against the move.
Significantly, John McDonnell and Barry Gardiner have now joined their Shadow Cabinet colleagues Tom Watson, Emily Thornberry and Keir Starmer in backing Remain, although party chairman Ian Lavery is still opposed.
Meanwhile, Mr Corbyn gave his strongest anti-Brexit comments yet in the Commons on Monday.
Responding to a statement by Theresa May on last week’s European Council, he said: “Will the Prime Minister tell us, whether she believes ‘no deal’ should be on the table as a viable option?
"And, in her view, what would be worse: crashing out with no deal in October, or putting this issue back to the people for a final say?"