Jeremy Corbyn, the leader of Britain's main opposition Labour party, has said it is "right to demand" a second referendum on any deal about the country's departure from the European Union, or Brexit.
Addressing his top policy team, Corbyn said on Wednesday that any such public vote should offer "real choices for both Leave and Remain voters".
"I have already made the case ... that it is now right to demand that any deal is put to a public vote. That is in line with our conference policy which agreed a public vote would be an option," he said.
"A ballot paper would need to contain real choices for both leave and remain voters. This will of course depend on parliament."
In the June 23, 2016 referendum, 17.4 million voters, or 51.9 percent, backed leaving the EU while 16.1 million, or 48.1 percent, supported staying. Critics of Corbyn said he did not work hard enough to persuade the party's voters to back remaining in the bloc
Corbyn, a long-standing critic of the EU, opposed the UK joining what was then the European Economic Community in 1975, then opposed the Maastricht Treaty - formally known as the Treaty on European Union - in the early 1990s and subsequently the bloc's 2008 Lisbon Treaty.
He has been under pressure to change his mind and campaign to remain in the EU, but a letter sent to him on Wednesday by 25 Labour MPs representing leave-voting constituencies maintained that Brexit must happen, "and without further undue delay".
"Labour has a vital role to play fighting for a Brexit for the many, not the few," read the letter. "But this is a battle best fought in stage two, after the UK has left."
Corbyn, who has been Labour leader since 2015, said he would still seek to consult with trade union groups before formally presenting his views to the public.
Earlier this week, deputy Labour leader Tom Watson said the party's "ambiguity" over the issue had hurt its performance in European elections.
The Labour leader has previously been criticised for sitting on the fence on the issue of Brexit, supporting the UK's withdrawal from the EU in principle, but demanding that any exit deal protects workers' rights.
He opposed Prime Minister Theresa May's negotiated agreement on those grounds, and has repeatedly called for a new general election.
With the Conservatives in the middle of a bitter leadership battle which hinges on competing visions of Brexit, both of Britain's leading parties have been haemorrhaging support to smaller parties with clear positions on the issue, making the outcome of a general election hard to predict.