LONDON — More than 500 people were arrested Saturday during a peaceful sit-down demonstration in Trafalgar Square against the British government’s ban on the direct-action group Palestine Action, as organizers accused officials of complicity in what they called Israel’s genocide in Gaza.

Metropolitan Police said 523 individuals, ranging in age from 18 to 87, were taken into custody for showing support for the proscribed organization. Officers carried away seated protesters — many holding signs reading “I oppose genocide. I support Palestine Action” — amid applause and chants from the crowd, in scenes that organizers described as a deliberate act of mass civil disobedience.

The event, dubbed “Everyone Day” and organized by the Defend Our Juries campaign, drew hundreds to central London on April 11, 2026. Participants sat on the steps and pavement of the iconic square, refusing to disperse despite police warnings. Arrests began in the afternoon and continued into the evening, with police confirming the total at 523 by late Saturday.

Protest leaders framed the demonstration as resistance to both the ongoing crisis in Gaza and what they called an unlawful crackdown on free speech at home. “The UK government is complicit in genocide,” said a spokesperson for Defend Our Juries. “While it arms Israel and blocks accountability, it criminalizes peaceful Britons for simply opposing that complicity.” Organizers estimated around 500 to 1,000 people took part, calling it one of the largest acts of defiance since the ban was imposed.

Palestine Action, known for disrupting factories and offices linked to Israeli arms manufacturers such as Elbit Systems, was proscribed as a terrorist organization under the Terrorism Act 2000 in July 2025. The designation made public support for the group a criminal offense punishable by up to 14 years in prison.

In February 2026, the High Court ruled the ban unlawful and said it should be quashed. The government appealed, however, and the prohibition remains in force pending the outcome. Following the court decision, Metropolitan Police initially paused arrests but later reversed course, announcing in March they would resume enforcement because the law had not changed.

Saturday’s rally marked the first major test of that policy since the U-turn. Police said all arrests were for “showing support for a proscribed organisation.” No serious injuries or violent incidents were reported, though some demonstrators needed assistance due to age or mobility issues. Videos circulating online showed officers gently lifting elderly protesters, including one woman using a cane, as the crowd clapped in solidarity.

Human rights groups and civil liberties advocates expressed alarm at the scale of detentions. Critics argued the mass arrests highlight a shrinking space for protest in the UK, especially on issues related to Gaza. Since the ban took effect, nearly 3,000 people have faced arrest for holding similar signs at vigils across the country, according to campaigners. Many cases remain pending in the courts.

A government spokesperson defended the proscription, stating that Palestine Action’s tactics — including property damage and disruption — crossed into criminal territory and posed a threat to public safety and national security. “The law applies equally to everyone,” the spokesperson said. “Support for a banned terrorist organization is a serious offense, regardless of the cause.”

Palestine Action has rejected the terrorist label, describing its activities as non-violent direct action aimed at shutting down what it calls “genocide-enabling” arms production in Britain. The group and its supporters point to UK arms exports to Israel and diplomatic backing as evidence of complicity in alleged war crimes.

The demonstration unfolded against the backdrop of continued international scrutiny of the Gaza conflict. Organizers repeatedly linked domestic protest rights to broader calls for a ceasefire, an end to arms sales and accountability for alleged atrocities. “This is not just about one group,” one arrested protester told reporters before being led away. “It’s about whether ordinary people can still speak out when their government is on the wrong side of history.”

Legal experts noted the unusual nature of the arrests. Holding a placard, even one supporting a banned group, has traditionally fallen under protected speech, but terrorism legislation gives authorities broad powers. Lawyers from firms such as Hodge Jones & Allen have argued that continued arrests could be challenged as unlawful, especially after the High Court ruling.

Saturday’s events drew comparisons to historic acts of civil disobedience, with some protesters dressing in suffragette-style attire to emphasize themes of democratic resistance. Organizers said the strategy of mass participation was designed to overwhelm the justice system and highlight what they see as disproportionate policing.

Metropolitan Police emphasized professionalism in a statement posted on social media. “We are grateful to all the officers involved,” it read, adding that resources had been deployed to maintain public order in a busy central London location on a spring weekend.

Trafalgar Square, a traditional site for large gatherings, remained cordoned off for much of the day. Tourists and passers-by watched as lines of officers moved through the seated crowd, making selective arrests based on visible signage. Some demonstrators tore up their placards just before police approached, while others held them defiantly until the moment of detention.

The arrests come amid wider tensions over pro-Palestinian activism in the UK. Large marches against the war in Gaza have occurred regularly since October 2023, but the specific targeting of Palestine Action supporters has intensified debate over balancing security concerns with civil liberties.

Opposition politicians and rights organizations called for an independent review of policing tactics. “Mass arresting pensioners for holding signs is not how a mature democracy handles dissent,” said one commentator aligned with civil liberties groups.

As night fell, processed detainees were transported to various stations for questioning and potential charging. Many are expected to be released on bail pending further investigation, though some could face court appearances in coming weeks.

The episode is likely to fuel ongoing legal battles. The government’s appeal against the High Court decision is pending, and campaigners have vowed to continue “Everyone Day” style actions until the ban is lifted and related charges dropped.

For now, the 523 arrests represent one of the largest single-day tallies at a political demonstration in recent British history. Organizers hailed the turnout as proof of widespread public opposition to both the Gaza policies and restrictions on protest.

“This government can ban groups and arrest citizens, but it cannot ban conscience,” a Defend Our Juries statement read. “We will keep coming back — everyone, every time — until justice prevails in Gaza and at home.”

Police said investigations into the arrests would continue, with priority given to processing the large volume of cases efficiently. No immediate updates on charges were available late Saturday.

The Trafalgar Square action caps a week of heightened activity around Palestine-related issues, including smaller vigils and legal hearings. It also underscores the persistent divide in British public opinion over the Middle East conflict and the limits of acceptable protest.

As the sun set over Nelson’s Column, the square slowly returned to its usual Saturday evening rhythm, but the images of mass arrests are expected to reverberate in political and legal circles for weeks to come.