Labour can “unite our country” and heal the divisions caused by Brexit, Jeremy Corbyn will say, as he launches his European elections campaign later.
Mr Corbyn will say the party backs “the option of a public vote” if a “sensible” Brexit deal cannot be agreed and there is not a general election.
He will say Labour will address the “inequalities that helped fuel” the 2016 Brexit vote.
The European elections take place in the UK on 23 May.
The UK was due to leave the EU on 29 March, but as no deal was agreed by Parliament, the EU extended the deadline to 31 October.
It can leave the bloc earlier, but if the UK has not left by 23 May, it is legally obliged to take part in the EU-wide poll and send MEPs to Brussels.
Mr Corbyn will launch Labour’s campaign in a Leave-supporting area of Kent, where he will issue an appeal to both sides of the Brexit debate.
He will say: “To transform our country, and tackle injustice, inequality and the climate crisis, we need to unite the overwhelming majority of people and take on the privileged and powerful.
“That’s why we insist the real divide in our country is not how people voted in the EU referendum.
“The real divide is between the many and the few.”
The party has selected 70 candidates across the 12 regions. They include the former cabinet minister and passionate Brexit critic Andrew Adonis, who is second on the South West England list.
Other stand-out names include Laura Parker, a leading figure in the Momentum campaign group, and Eloise Todd, chief executive of the Best for Britain group.
Mr Corbyn will say Labour “is the only party with a plan to unite our country”.
“Other parties appeal to just one side of the Brexit debate because they aren’t really committed to taking on the tax dodgers, the big polluters, or the financial gamblers who crashed our economy a decade ago,” he will say.
He will say Labour’s alternative plan for Brexit “would end the chaos caused by the Conservatives and let us focus on the other big issues facing our country”.
“But we can never accept the government’s bad deal or a disastrous no deal,” he will say.
“So if we can’t get a sensible deal, along the lines of our alternative plan, or a general election, Labour backs the option of a public vote.”
The issue of a further referendum has proved divisive in the party – with many MPs and frontbenchers opposed to the idea.
But Labour’s governing body agreed last month to support a further referendum on Brexit under certain circumstances.
Meanwhile, cross-party talks between the government and Labour have been taking place to try to solve the Brexit impasse.
Downing Street and Labour confirmed the talks will continue next week.
Sir Graham Brady, chairman of the 1922 Committee of Tory MPs, said on Wednesday that he believed the PM would ask the Commons to vote again on the terms of the UK’s exit before elections to the European Parliament take place.
The withdrawal agreement has effectively been rejected by MPs three times already.