Boris Johnson has claimed the UK would be “gravitationally sucked back into the orbit of the EU” under a Labour government.
The former prime minister said an “interesting situation” would emerge under a Sir Keir Starmer-led administration.
He will make the claim on a new talk show hosted by his former culture secretary Nadine Dorries, who aggressively backed him when his scandal-hit premiership came to an end last summer.
Starmer campaigned for Remain in the 2016 referendum and then called for a second referendum in the subsequent years of constitutional turmoil. However, since becoming Labour leader in 2020, he has repeatedly ruled out rejoining the EU.
This week, David Lammy, one of his senior shadow cabinet members, also said rejoining the EU was not an option - but that Labour would “fix the Tories’ bad Brexit deal” brokered by Johnson.
Johnson’s full interview will air on TalkTV on Friday. In quotes reported by The Sun, which like TalkTV is owned by News UK, Johnson will say of the UK-EU relationship under a Labour government: “I think that you’d have a very interesting situation, they would be gravitationally sucked back into the orbit of the EU.
“I think that would be very wrong for the country.
“It would lose us a lot of opportunities that we currently have.”
Watch: A Labour government would ‘fix bad Tory Brexit deal’, says David Lammy
In his speech on Wednesday, shadow foreign secretary Lammy said Labour would take action to reverse the “damage” the current UK-EU trade deal is doing to the British economy, while also restoring European relations.
He added: “It has been a central principle of British strategy for centuries that we should never find ourselves isolated in our own continent. But that is exactly what this government has done.”
Three years on from the UK's departure, the Northern Ireland Protocol, signed off by Johnson as part of his Brexit deal, remains a key source of tension between the UK and the EU as the two sides bid to find a solution.
The row over the protocol, which unionists say creates a border between Northern Ireland and the rest of the UK, effectively led to the collapse of power sharing in Stormont.
Meanwhile, Michel Barnier, who was the EU's chief Brexit negotiator, today refused to acknowledge mistakes were made on the EU's side, with Ireland's prime minister Leo Varadkar conceding earlier this month that the protocol is “too strict” and mistakes were made on all sides during negotiations.
Speaking on the BBC's Sunday with Laura Kuenssberg show, Barnier said: "I think we [left] a certain number of points open for the discussion. I don't think [you] can speak of mistakes."