London's Metropolitan Police Service arrested dozens of people on July 30, 2026, at a rally outside Westminster Magistrates' Court where demonstrators expressed support for Palestine Action, a group proscribed as a terrorist organisation under UK law. Al Jazeera

The rally was organised by the activist group Defend Our Juries, which had called supporters to picket the start of hearings against individuals charged with voicing support for Palestine Action. A plea hearing for 25 people accused of showing support for the proscribed organisation was taking place at the court the same day. The exact number of arrests at the July 30 rally has not been specified; Al Jazeera described it only as "dozens."

The Metropolitan Police had issued an explicit warning the evening before. At 19:00 on July 29, the force published a news release on its website stating that officers would be deployed in the vicinity of Westminster Magistrates' Court and cautioning Palestine Action supporters that they faced arrest. On the day of the rally, the force posted on X: "Expressing support for Palestine Action is an offence under the Terrorism Act. Officers have begun making arrests."

The legal basis for these arrests traces to the UK's proscription of Palestine Action as a terrorist organisation. Under Section 12 of the Terrorism Act 2000, expressing support for a proscribed organisation is itself a criminal offence — a provision that has now been applied systematically to individuals publicly aligning with the group.

This is not an isolated enforcement event. The Crown Prosecution Service announced in September 2025 that it would prosecute 24 people for showing support for Palestine Action. By October 2025, the UK government reported that almost 500 people had been arrested under new police powers, with most of those arrests made for supporting the proscribed group. gov.uk

The trajectory of arrests has escalated sharply through 2025 and 2026. Reuters reported that the Metropolitan Police arrested more than 365 people at a pro-Palestine Action protest on August 9, 2025. On April 11, 2026, London police arrested 523 people at a protest over the Palestine Action ban, according to Reuters. The following day, Le Monde reported that nearly 3,000 arrests had been made since the ban was imposed, mainly for carrying placards defending the group. Reuters

The cumulative arrest figure approaching 3,000, as reported by Le Monde in April 2026, places the UK's enforcement of proscription-related offences at a scale that invites comparison with the application of counter-terrorism powers against dissident republican groups in Northern Ireland during the 1990s. The enforcement pattern has several notable features. First, the offences being prosecuted — chiefly the public expression of support, including the display of placards — are expressive acts, not charges of material support, violent conduct, or operational assistance to a proscribed organisation. The legal architecture being applied here treats the act of advocacy itself as the harm to be prevented, which is consistent with the Terrorism Act's design but nonetheless places these prosecutions at the expressive edge of counter-terrorism law.

Second, the pre-emptive posture of the Metropolitan Police is notable. The force published its warning the evening before the July 30 rally, naming the location and signalling that arrests would follow. This is not reactive policing of a demonstration that turned disorderly; it is a pre-declared enforcement operation against an announced act of public expression, conducted by an activist group — Defend Our Juries — that explicitly set out to challenge the legitimacy of prosecuting individuals for jury-related protest and for voicing support for Palestine Action.

Third, the coordination between the CPS, the government, and the Metropolitan Police suggests an institutional commitment to sustained prosecution rather than a one-off deterrent action. The September 2025 CPS announcement of further prosecutions, the October 2025 government announcement of new police powers, and the repeated large-scale arrests through 2025 and 2026 indicate that the state apparatus has converged on a policy of comprehensive enforcement.

The wider stakes involve the boundary between counter-terrorism law and the right to political expression in the UK. The European Convention on Human Rights, incorporated into domestic law through the Human Rights Act 1998, protects freedom of expression under Article 10, but that right is qualified — it can be restricted for reasons including national security and public safety, provided the restriction is prescribed by law and proportionate. The proscription regime under the Terrorism Act 2000 represents a statutory restriction, and Section 12 offences have historically been upheld as lawful limitations. The question that these cases foreground is one of proportionality: whether mass arrest and prosecution of individuals for carrying placards or vocalising support for a proscribed group clears that threshold, and whether the criminal courts will treat the expressive nature of the conduct as a mitigating factor at sentencing or as irrelevant to the question of guilt.

For now, the enforcement pipeline shows no sign of contracting. The July 30 rally was met with the same legal framework that produced 523 arrests in April and 365 in August 2025. Each court hearing — including the 25 plea hearings at Westminster Magistrates' Court this week — generates fresh defendants, fresh demonstrations, and, in turn, fresh arrests under the same statute.