Members of the anti-Brexit Our Future, Our Choice, a youth movement supporting a People's Vote on the Brexit deal, demonstrate outside the gates to Downing Street in London on August 28. British Prime Minister Boris Johnson announced that the suspension of parliament would be extended until October 14. Photo: AFP

Labour leader Jeremy Corbyn's moment of truth comes with the crisis-torn country hurtling toward an October 31 exit from the European Union without a plan for future trade.

Yet the same divisions over Europe that saw Boris Johnson's right-wing Conservatives lose their working majority are also tearing apart Labour on the left.

The 119-year-old party's support base consists of cosmopolitan city-dwelling europhiles and traditional working-class communities that rejected Brussels in the 2016 referendum.

Polls show these views have become even more entrenched on Sunday - a polarization that further complicates Corbyn's bid to find a unifying stance.

The strongly anti-European Brexit Party and the pro-EU Liberal Democrats are eroding Labour's support on both flanks, according to recent polls.

Labour officials will hunker down in a swanky hotel on England's south coast Sunday night to whittle down their Brexit options to a single position that will be either rejected or approved Monday.

Corbyn has given every indication that he wants Labour to stay neutral on the defining issue of UK politics.

"No, I am not sitting on the fence," he insisted in a testy ITV interview Friday.

He has promised to negotiate a new divorce deal that maintains closer EU relations and then hold another referendum in which remaining in the bloc is the other option.

But he would not say which of the two he would campaign for - or whether he actually wants to stay or go.

"The British people will make that final decision," Corbyn told ITV.

Efforts to keep the peace by appeasing both wings of his party are not sitting well with voters ahead of an early election that most expect to happen within months.

A September YouGov survey showed that just half of self-identifying Labour supporters trust Corbyn's ability to "make the right decisions on Brexit."