Sir Sadiq Khan called on the Labour Party to promise to rejoin the European Union at the next general election, putting him at odds with the prime minister who has repeatedly ruled out undoing Brexit and returning to the bloc.
Speaking to the Italian newspaper La Repubblica, the Mayor of London outlined a roadmap for closer ties, including returning to both the customs union and the single market.
Sir Sadiq, who played a leading role in resisting the UK’s departure from the EU, now believes there is a route back to membership.
In the interview he highlighted Brexit’s detrimental impact, stating: “I see on a daily basis the damage Brexit has done to not just London, but to Londoners, the damage economically, socially and culturally.” Sir Sadiq was unequivocal: “I’m quite clear in terms of what needs to happen, which is, we should join the European Union.”
The mayor cited the election of US President Donald Trump, growing global instability, and the passage of time as reasons to revisit the issue, arguing “the facts have changed” and “the evidence has changed”. He insisted: “We should, as a Labour Party, fight the next general election with a clear manifesto commitment, a vote for Labour means we would rejoin the European Union. I think it’s inevitable.”
But it comes after European affairs minister Nick Thomas-Symonds, who is in charge of the reset negotiations between Britain and the EU, told The Independent that he could not envisage the UK ever rejoining the bloc and ruled out any form of customs union.
He said: “I don’t see us [rejoining]. I don’t see us returning to the debates of the past.”
Prime Minister Sir Keir Starmer has sought to “reset” relations with Brussels in an effort to improve trade ties since his election in 2024, and earlier this week chancellor Rachel Reeves warned the UK risked being “stranded” between rival trading blocs unless it forged closer ties with Brussels.
She said any divergence from EU regulations would be limited, describing it as “the exception, not the norm”.
Ms Reeves added: “Our fate as a country is inescapably bound with that of Europe.”
By the time of the next joint summit later this year, the UK and EU want to finalise agreements on a youth mobility scheme, as well as establishing a common sanitary and phytosanitary area and on linking their emissions trading systems.
In February, Downing Street dismissed the prospect of rejoining the customs union after European economic commissioner Valdis Dombrovskis said the bloc would be open to discussions.
No 10 sought to pour cold water on the idea, saying Sir Keir Starmer’s government would be sticking to its red lines as it deepens ties with the EU.
The prime minister’s official spokesman said: “We will not be rejoining the customs union, the single market or returning to freedom of movement.
“Those are our red lines as per the government’s manifesto.
“We do want a closer economic partnership with the EU, but rejoining the customs union would unpick important trade agreements we’ve reached, including our deals with the US and India.”

