JOHN McDonnell has suggested that “white smoke” can be expected from Labour on a second EU referendum today when the Shadow Cabinet meets to thrash out the party’s policy on Brexit.

The Shadow Chancellor told an audience in the City to “watch this space” when it was suggested Jeremy Corbyn might be willing to finally support another vote on EU membership in all circumstances.

But after talks between the Labour leader and trade union chiefs ahead of the Shadow Cabinet meeting, it emerged that the movement’s divisions on EU withdrawal remained deep-seated.

Len McCluskey, the General Secretary of Unite, Labour’s biggest donor, made clear his union’s continued opposition to holding a second referendum as did Dave Ward, leader of the Communication Workers Union, who set his organisation’s face against Labour campaigning for Remain.

However, every other union, including Unison and the GMB is believed to have urged Mr Corbyn to support staying in the EU, a position supported by Tom Watson, the deputy leader, Mr McDonnell and the Scottish Labour Party.

The position from last year’s party conference is to push for a general election or an acceptable deal on Brexit before considering a public vote.

However, senior figures in the party believe events have moved on; that there is little chance of an election or getting a good deal on Brexit and that any future deal the Government manages to agree and get through the Commons must be put to a confirmatory referendum with Labour campaigning for Britain to stay in the EU; a position the Scottish party adopted earlier this month.

Mr Corbyn has so far resisted making explicit Labour's position; a number of his MPs representing Leave-backing constituencies have called on him not to do so.

Caroline Flint, who represents Don Valley in South Yorkshire, is one of 26 Labour MPs who have urged their party leader not to call for a second referendum, saying she would prefer no-deal to no Brexit.

While Mr Corbyn has pointed to party conference in the autumn as the forum to make clear Labour’s Brexit policy, colleagues are demanding he set it out before the start of the parliamentary recess on July 25.

He is expected to make a public statement on Labour's Brexit policy later this week; Mr McDonnell said today’s Shadow Cabinet meeting would be solely focused on the subject.

"Out of Shadow Cabinet…I’m hoping that a more definitive position will emerge," he said.