Labour’s deputy leader Tom Watson is stepping up pressure for a shift in the party’s Brexit stance within the coming weeks, after a meeting for the shadow cabinet to thrash out the issue was called off at short notice.
In an impassioned speech on Monday, Mr Watson called for Labour to throw its weight whole-heartedly behind the campaign for a Final Say referendum, arguing the party should be “loud and proud” in its support for remaining in the EU.
But no new date has yet been fixed for the shadow cabinet showdown, and sources close to Watson said he was concerned that time was running out for the party to make an impact ahead of the 31 October deadline for Brexit.
Jeremy Corbyn has previously suggested Labour could wait until its annual conference in Brighton in September to consider amending its policy of seeking a general election before a fresh referendum.
But Mr Watson believes this is too late, and a change of position must be agreed by the start of the summer.
Mr Corbyn came under fire from backbench MPs at a meeting of the Parliamentary Labour Party last week over his refusal to switch stance in the wake of the party's disastrous third place on 14 per cent of the vote in European elections.
“The majority of Labour MPs want a change of position and they want it soon,” said a source close to the deputy leader. “They feel that the summer is a chance to go out and make the positive case for a People’s Vote and Remain.
“Conference is too late. Labour urgently needs to start making the case for Remain. We need to use this time while the Tories are scrapping over their new leader.”
In his speech, Mr Watson rejected suggestions that Labour must back Brexit to hold onto the support of traditional working-class voters.
EU funding had been “a lifeline for so many traditional Labour areas and working-class communities” under successive Conservative governments, and the EU was “a friend to workers here and across the continent”, he said.
“European is who we are and who we have always been,” said Mr Watson.
“Our members are remain. Our values are remain. Our hearts are remain.
“We need our Labour Party to be true to who we are and be loud and proud in support of Europe.”
Labour MP David Lammy, a prominent supporter of the Best for Britain campaign for a second referendum, said: "Tom is absolutely right. My party should be making the case for staying in the EU loudly and proudly.
"We should be making that case because our dreams of transforming this country are best aided inside the EU, not out in the cold having wrecked our economy.
"And beyond that, we should be making the case for staying in because we are internationalists. We cannot be happy just transforming the UK - we must have bigger ambitions than that. We want to change the lives of working people around the world and the EU can help."
A spokeswoman for Mr Corbyn’s office confirmed that Monday’s shadow cabinet meeting was postponed because a number of shadow ministers were unable to attend, and that no new date has yet been scheduled.
Liberal Democrat Brexit spokesman Tom Brake said: “Tom Watson’s challenge to Jeremy Corbyn to back that campaign is more than welcome, but must be backed up with action.
“Jeremy Corbyn remains a block in the road. Despite the public punishing the Labour party at the European elections for their clear-as-mud position on Brexit, the Labour leader is still refusing to give up his personal obsession with taking the UK out of the EU.
“If Jeremy Corbyn refuses to budge, Labour MPs must be ready to remove him. Meanwhile, Liberal Democrats will continue to fight tooth and nail to give people the final say, with the option to stop Brexit.”