Shadow chancellor John McDonnell has confirmed Labour will put down an amendment to call for a second referendum after the next meaningful vote.
Speaking to ITV's Peston, Mr McDonnell explained that Labour would push for another referendum if Theresa May's Brexit deal was rejected by Parliament.
"When the meaningful vote comes back, and we are told maybe that might be on March 12, there are rumours today [Wednesday] that it could be next week, we will see.
"That's the time when we will have to put the amendment up."
But he added: "We are still going to argue that we want a general election, we are still going to argue we think our deal that we have put up was the best option.
"But we realise... we have got to break this deadlock."
He suggested "either a deal will go through which will protect jobs and the economy or, to get some deal through, it will be conditional on going back to the people".
Mr McDonnell confirmed that if there were to be a second referendum, that he would vote to remain in the EU.
He also told ITV News' Political Editor that the more focus there is on jobs and the economy in terms of Brexit, the more likely it is that "a deal will go through that will protect jobs and the economy, or to get some deal through, it will be conditional on going back to the people".
However, also on the programme was fellow Labour MP Lisa Nandy, who said many Labour-backers and even members of the shadow cabinet were dismayed at the Party's move to back a second referendum.
A large number of Labour seats backed Leave in the June 2016 referendum.
Tory MP Oliver Letwin, who had been due to table an amendment to postpone Article 50 if no-deal loomed, but withdrew his support for it after Mrs May's announcement earlier this week, acknowledged that Parliament is deeply divided over Brexit and that there should be a number of votes to see where the consensus lies.
Watch Peston on ITV at 11.10pm on Wednesday 27 February