The US vice-president, JD Vance, has urged anti-immigration activists in the UK to “keep on going” after tens of thousands gathered for a rally in London.

Vance appeared to align himself with those who attended a march on Saturday where the far-right activist Tommy Robinson told supporters to prepare for the “battle of Britain”.

Organisers claimed that millions had attended his “unite the kingdom” event, but police estimated the number of demonstrators to be far lower, at about 60,000. The campaign group Hope Not Hate nevertheless said the scale of Robinson’s movement remained “deeply worrying”.

Addressing reporters at the White House on Tuesday, Vance claimed that “all over the west” there is “this idea that the way to generate prosperity is to bring in millions and millions of unvetted people and drop them into your neighborhoods”.

“And we simply reject that idea,” he said. “To everybody in the UK who rejects that idea, I’d encourage them to just keep on going. It’s OK to want to defend your culture. It’s OK to want to live in a safe neighborhood.”

At Saturday’s rally in London’s Parliament Square, Robinson, whose real name is Stephen Yaxley-Lennon, claimed the event was “a turning point for Britain”.

Islamophobic and ethnonationalist hate speech and flyers were distributed to the crowds at the event, where nine people were arrested on suspicion of hate crimes.

Vance framed his support on Tuesday in economic terms, arguing that mass immigration drives down wages and harms working people on both sides of the Atlantic – including, he claimed, lower-income Black and Hispanic Americans in the US.

Saturday’s march was the latest in a series of Robinson-organized demonstrations. A rally in September drew up to 150,000 people into the streets of London, where Elon Musk addressed the crowd by video link. The UK police are confident the latest event was less than half the size.

Keir Starmer, the prime minister, said before the march that he supported the right to peaceful protest, but accused the organizers of peddling hatred and division. His government said it had blocked entry visas for foreign far-right figures who had sought to attend.

Robinson has been a key figure in British far-right politics for more than a decade, and has now seeped into the American rightwing influencer ecosystem.

He co-founded the English Defence League in 2009 and has since built a string of criminal convictions, including mortgage fraud, assault and repeated contempt of court charges for filming defendants in active criminal trials. The most recent sent him to prison in 2024.

Earlier this year, the UK home secretary, Shabana Mahmood, ripped up the government’s asylum rules so that newly recognized refugees will receive just 30 months of temporary protection rather than the previous five years.

The EU will also fully adopt a sweeping new pact on migration and asylum next month, overhauling how the bloc screens, processes and shares responsibility for asylum seekers at its external borders.