More than 300 people have been arrested during a protest in support of the banned Palestine Action group, held outside the US Embassy in London on Saturday.

Hundreds of demonstrators gathered at Nine Elms, many holding signs reading phrases such as "I oppose genocide, I support Palestine Action."

The Metropolitan Police said on Sunday that 325 arrests were made. Of those, 320 were for "expressing support for a proscribed organisation under the Terrorism Act," the force stated on social media. An earlier report cited a figure of 139 arrests, with the majority on the same suspicion.

Officers made arrests throughout the day and into the evening, escorting demonstrators to police vans to the applause of many in the crowd, some of whom chanted "Free, free Palestine." In some instances, officers had to carry protesters who refused to walk.

Palestine Action was proscribed in July 2025. The UK Supreme Court is due to review the ban after the group's co-founder was granted permission to appeal it. The Home Office has said it will robustly defend against the appeal.

Defend Our Juries, which has been co-ordinating a series of protests over the ban, said the number of people detained this weekend brought the total past 4,000 since the group was proscribed, calling the situation "truly dystopian."

According to Home Office figures, 3,630 arrests were made in the year ending June 2026. Combined with 134 people arrested outside Westminster Magistrates Court earlier this year and those detained on Saturday, the cumulative total stands at 4,089.

Retired lawyer Charles Allison, 75, who travelled from Cumbria to attend and was taken by police during the afternoon, said he feared for people's civil liberties, which he described as "being devalued and watered down."

"I hope the Supreme Court justices - they won't necessarily be influenced by it [the protest] - but I hope that they will take a long-term view of what is happening in this country and decide that the proscription was unlawful, as I believe it was," he said.

Another protester, David Bolden, who was awaiting arrest at the scene, called the ban an "absurd law."

Amnesty International UK has criticised the arrests and called on the government to drop the proscription of Palestine Action. Defend Our Juries also condemned the detentions as "unjust" and an assault on free speech.