More than 50 Labour parliamentary candidates have signed a pledge to campaign to Remain at a second referendum.
Jeremy Corbyn has pledged to negotiate a new Brexit deal with the EU and put it to a public vote within six months of taking office if he wins the election.
The referendum would be a choice between Labour’s exit deal and Remain.
Corbyn himself has repeatedly refused to say which way he will vote in the referendum he has pledged to hold.
Other senior Labour figures, including Shadow Chancellor John McDonnell, Shadow Brexit Secretary Keir Starmer and Shadow Foreign Secretary Emily Thornberry have all previously said they would back Remain.
On Friday more than 50 Labour parliamentary candidates, including returning MPs and those seeking reelection, signed a pledge to campaign in favour of EU membership.
The pledge reads: “Labour is committed to a confirmatory referendum, to give you a final say on Brexit. If elected as your Labour MP, I pledge to campaign to Remain in the EU.”
Andrew Lewin, founder of Remain Labour, the said: “The only route to staying in the EU is through electing a Labour government on December the 12th.
“The party is already committed to putting Brexit back to the people and I am delighted that more than 50 parliamentary candidates have already pledged to campaign to Remain in the EU in all circumstances.
“Remain voters want to vote for the Labour Party with confidence at this election. Our pledge will help candidates in England, Scotland and Wales to underline that the Labour Party is the strongest Remain Alliance in the country.”
It comes as the Lib Dems, Plaid Cymru and the Green Party formed an election pact, agreeing not to stand against each other in dozens of seats.
The deal, brokered by the Unite to Remain group, will give voters a single Remain choice in 60 constituencies across England and Wales. The group is confident that “at least 44” of the 60 seats are “highly winnable”.
The group said Labour was approached to take part, but said no.
Labour candidates standing to be re-elected:
Tonia Antoniazzi, Gower
Margaret Beckett, Derby South
Ben Bradshaw, Exeter
Ruth Cadbury, Brentford and Isleworth
Janet Daby, Lewisham East
Geraint Davies, Swansea West
Thangam Debbonaire, Bristol West
Stephen Doughty, Cardiff South and Penarth
Rosie Duffield, Canterbury
Maria Eagle, Liverpool and Halewood
Paul Farrelly, Newcastle-under-Lyme
Vicky Foxcroft, Lewisham Deptford
Helen Hayes, Dulwich and West Norwood
Darren Jones, Bristol North
Susan Jones, Clwyd South
Ged Killen, Rutherglen and Hamilton West
Peter Kyle, Hove
David Lammy, Tottenham
Kerry McCarthy, Bristol East
Siobhain McDonagh, Mitcham and Morden
Alison McGovern, Wirral South
Catherine McKinnell, Newcastle upon Tyne
Anna McMorrin, Cardiff North
Ian Murray, Edinburgh South
Stephen Morgan, Portsmouth South
Madeleine Moon, Bridgend
Matthew Pennycook, Greenwich and Woolwich
Steve Reed, Croydon North
Ellie Reeves, Lewisham West and Penge
Andy Slaughter, Hammersmith
Wes Streeting, Ilford North
Paul Sweeney, Glasgow North East
Jo Stevens, Cardiff Central
Gareth Thomas, Harrow West
Anna Turley, Redcar
Daniel Zeichner, Cambridge
Candidates standing to be elected:
Marina Ahmad, Beckenham
Callum Anderson, South West Bedfordshire
Fleur Anderson, Putney
Karen Davis, Norwich North
Pam Duncan-Glancy, Glasgow North
Rachel Eden, Reading West
Flo Eshalomi, Vauxhall
Dan Greef, South Cambridgeshire
Faten Hameed, Glasgow Central
Peter Lamb, Crawley
Martin McCluskey, Inverclyde
Cheryl Pidgeon, Rushcliffe
Moira Ramage, Paisley and Renfrewshire
Matt Uberoi, Chelsea and Fulham
Emma Whysall, Chipping Barnet