The hopes of voters who want Britain to ditch Brexit received a boost after Change UK said it could form an electoral pact with the Liberal Democrats.Former Labour MP Chuka Umunna, the party’s spokesman, said the parties should agree not to stand against each other in the next general election.He said politicians who want Britain to remain in the EU need to work “even more closely together” following the European elections.It comes after his party’s leader, Heidi Allen, admitted she threatened to quit in an internal row over tactical voting to maximise the pro-remain challenge to Nigel Farage’s Brexit Party.Mr Umunna told BBC Radio 4’s Today Programme on Saturday: “The remain forces in this country need to work even more closely together than we have managed to achieve up to this point between now and the general election.”Asked if Change UK could form a pact with the Liberal Democrats – similar to the alliance between the SDP and the Liberal Party in the 1983 general election – where their candidates do not stand against each other, Mr Umunna said: “I think it would be sensible.”He added: “I personally don’t think we should be competing at a general election and, of course, whilst we had a system of proportional representation at the European elections, it’s going to be first past the post in a general election, so we have got to get our ducks in a row and work out what configuration is appropriate for 2019 and beyond instead of just perhaps using the same model from the 1980s.” Ms Allen was asked earlier this week if she had threatened to quit as Change UK leader over an internal dispute over whether to publicly back the Liberal Democrats outside London and the South East. She told Channel 4 News: “Yes. I did. I am very, very troubled by this. This is a massive decision for a party to take. Had it been left to me, I would have absolutely advised tactical voting.”Ms Allen, who left the Conservative Party to join other breakaway Tory and Labour MPs, said the majority view was that “they didn’t want to go that way”.She added: “But it is something that still troubles me. I have no doubt that the British public will look at the tactical voting websites out there and make their own decisions.”Change UK was founded in April, two months after a number of Labour and Conservative MPs left their respective parties and joined forces as The Independent Group, following growing dissatisfaction at the way Brexit and other major political issues were being handled by the two main parties.It has 11 MPs in Parliament, but has been dogged by basic setbacks since its launch, including the failure to join forces with other Remain-backing parties in the Peterborough by-election. The party had been in talks with the Lib Dems, Greens and Renew about standing a single candidate in the vote on 6 June.The plan collapsed, however, after the unnamed candidate pulled out just hours before the deadline for submitting nomination forms. Change UK leader Heidi Allen speaking during Cardiff’s Principality Stadium on May 13Credit: Mark Hawkins / Barcroft Images Want the best of The Telegraph direct to your email and WhatsApp? Sign up to our free twice-daily Front Page newsletter and new audio briefings.