(Adds David Lammy)

Labour should back a second referendum on Brexit if its members want one, deputy leader Tom Watson has said.

Mr Watson’s comments came as a poll for The Observer found 86% of Labour members think voters should have the final say on the outcome of Brexit negotiations, and 90% would now vote to remain in the EU.

Labour has never taken the option of a second referendum off the table, but leader Jeremy Corbyn has made clear he would prefer the issue to be resolved through a general election.

The Independent reports that plans have been discussed within the party for a Commons vote of no confidence in the Prime Minister to force an election if she fails to get her Brexit plan through Parliament later this autumn.

Mr Corbyn is set to face intense pressure at the party’s annual conference in Liverpool to commit Labour to a second referendum.

MPs and union leaders are expected to join a march on the opening day of the conference on Sunday to demand a so-called “People’s Vote”.

And more than 100 constituency parties have submitted motions calling for the issue to be put to a vote. Many activists believe that with Mrs May’s plans in disarray following the rejection of her Chequers proposals by EU leaders in Salzburg, the time is now right for Labour to throw its weight behind a fresh ballot.

The YouGov survey of more than 1,000 Labour members found 86% support a referendum on the outcome of Brexit talks, against just 8% who oppose it.

Even in the North and Midlands, where many Labour constituencies voted Leave in 2016, there was overwhelming support – 86% and 88% respectively – for a second vote.

Some 81% believe their standard of living would get worse after Brexit and 89% said it would be bad for jobs.

Labour Party annual conference 2018A red flag flies as Labour leader Jeremy Corbyn speaks at a rally at Pier Head in Liverpool, ahead of the party’s annual conference in the city (Stefan Rousseau/PA)

Mr Watson told The Observer: “Jeremy and I were elected in 2015 to give the Labour Party back to its members.

“So if the people’s party decide they want the people to have a final say on the deal, we have to respect the view of our members and we will go out and argue for it.”

But shadow chancellor John McDonnell warned on Saturday that a second referendum could stoke racial tensions and far-right populism.

“I really worry about another referendum,” said Mr McDonnell.

“I’m desperately trying to avoid any rise of xenophobia that happened last time around, I’m desperately trying to avoid giving any opportunity to Ukip or the far-right. I think there’s the real risk of that.

“We’re not ruling out a people’s vote, but there’s a real risk, and I think people need to take that into account when we’re arguing for one.”

Former foreign secretary David Miliband said it was an “absolute dereliction of duty” for Labour not to say that the deal obtained by the Prime Minister must be put to the people.

Mr Corbyn told an eve-of-conference rally in Liverpool: “If this Government can’t deliver, then I say to Theresa May the best way to settle this is to have a general election.”

The rally was punctuated by cries of “stop Brexit” from the audience, but most speakers steered clear of the topic, ahead of a conference which Labour wants to focus on housing and workplace rights.

Pro-EU MP David Lammy, who backs the People’s Vote campaign, said: “Labour is a democratic party that under Jeremy Corbyn’s leadership has given its members and supporters a bigger voice in how it is run than ever before.

“It is so important now, at this vital moment for our country and our communities, that our party listens to its members, listens to its voters and listens to those we need to convince if we are to have that radical Labour government we need.”

– YouGov interviewed 1,054 Labour members between September 13 and 18.