Sir Keir Starmer has said he will be seeking a closer trading relationship with the EU if Labour wins the next election.
The Labour leader spent the weekend meeting fellow centre-left leaders in Montreal, Canada, including the country’s prime minister Justin Trudeau.
It comes amid a flurry of overseas engagements before party conference season, with Sir Keir expected to meet French President Emmanuel Macron later this week.
Speaking to The Financial Times, the frontrunner to become the next prime minister said he would be seeking a rewritten Brexit deal.
Labour has long been critical of the deal negotiated by the Conservatives under Boris Johnson, with the Trade and Cooperation Agreement up for review in 2025.
Sir Keir told the paper: “Almost everyone recognises the deal Johnson struck is not a good deal – it’s far too thin.
“As we go into 2025 we will attempt to get a much better deal for the UK.”
Labour has ruled out rejoining the customs union or single market, but Sir Keir said he was confident a better deal could be secured from Brussels.
“I do think we can have a closer trading relationship as well. That’s subject to further discussion.”
“We have to make it work. That’s not a question of going back in. But I refuse to accept that we can’t make it work. I think about those future generations when I say that.
“I say that as a dad. I’ve got a 15-year-old boy and a 12-year-old girl. I’m not going to let them grow up in a world where all I’ve got to say to them about their future is, it’s going to be worse than it might otherwise have been.
“I’ve got an utter determination to make this work.”
Sir Keir earlier said it was “complete garbage” to suggest Labour planned to join an EU-wide migrant quota scheme as part of efforts to tackle small boat crossings in the Channel.
It comes after the Prime Minister Rishi Sunak and Home Secretary Suella Braverman accused Labour of planning to let the UK become a “dumping ground” for 100,000 migrants from the EU each year.
The political row emerged after the Labour leader indicated he could be prepared to do a deal with Brussels which would involve the UK taking a quota of asylum seekers who arrive in the bloc in exchange for the ability to return people who cross the English Channel.
“The idea that we’re going to join the EU scheme on quotas is complete nonsense. We’re not an EU member and that wasn’t what I was talking about,” he told Sunday Morning with Trevor Phillips on Sky News.
Senior Labour figure Pat McFadden, questioned on the same issue on BBC One’s Sunday With Laura Kuenssberg, said: “I don’t think it’s going to be an allocation of numbers, we’re talking about individual cases where a child may have strong family links here.
“It’s not ‘we’ll take this many, you take that many’ – that’s not the kind of negotiation we want to have.”
Labour is also facing renewed pressure from its main union backer Unite, which is reportedly set to launch a grassroots campaign to call for more radical policies on energy and steel.
Unite general secretary Sharon Graham, who has called for public ownership of energy and has been critical of Sir Keir in the past, told The Guardian the union would be targeting so-called “red wall” areas as part of a bid to put pressure on the Labour leadership.