Police arrested more than two dozen supporters of activist group Palestine Action outside the UK Supreme Court on Wednesday as justices heard the group’s challenge to its designation as a terrorist organisation.
The group has been fighting the government’s ban under anti-terrorism laws, which has led to the arrests of more than 3,000 of its supporters over the past year.
The government outlawed Palestine Action after activists broke into a Royal Air Force base in June 2025 to protest British military support for Israel’s offensive in Gaza, which has killed tens of thousands of Palestinians. The break-in followed other acts of vandalism by the group.
Britain's interior ministry has argued that the group's escalating actions, causing serious property damage, particularly a 2024 raid targeting Israeli defence firm Elbit Systems, amounted to terrorism and justified the ban.
The designation places Palestine Action in the same legal category as al-Qaida and Hamas and makes membership in or support for the group punishable by up to 14 years in prison.
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Palestine Action supporters and civil liberties groups say the arrests of peaceful protesters have violated their rights to free speech and protest.
A lower court ruled that the government acted unlawfully in banning the group, but five Court of Appeal judges reversed that decision in June.
A lawyer for the group told the court Wednesday that only three of its 385 actions over five years met the legal definition of terrorism, and only because they involved property damage.
Of nearly 100 proscribed organisations, Palestine Action is the first to be banned solely for causing serious property damage, "with no suggestion that it advocated serious violence," lawyer Raza Husain said.
Government lawyer James Eadie said the Court of Appeal had rejected the characterisation of Palestine Action as a "non-violent direct action protest group." Serious property damage could constitute terrorism without violence against people, he said.
Eadie said protesters could legally support Palestine and oppose Israel as long as they did not back Palestine Action.
Outside the court, protesters sought to highlight what they described as a different policing standard for them and Sarah Helm, the wife of UK national security adviser Jonathan Powell.
After British booksellers were banned last month from selling works by Irish novelist Sally Rooney because of her financial support for Palestine Action, other authors defended her on social media.
Among them was Helm, who wrote on X: "God help us authors who support Palestine and Palestine Action."
London’s Metropolitan Police reviewed her post and decided it was not a crime.
On Wednesday, protesters held signs with similar wording, replacing "authors" with descriptions such as "normal people," "students" and “sons of Holocaust survivors."
The last person arrested was a woman who had held a sign reading: "God help us who are not married to the UK’s national security adviser who support Palestine and Palestine action."
“Sarah Helm had the same sign as me,” she shouted in protest.
Palestine Action was founded in 2020, when activists smeared red paint on the London headquarters of Israeli weapons manufacturer Elbit Systems UK. It gained prominence after Israel launched its military offensive in Gaza following Hamas’ Oct. 7, 2023, attack, which killed about 1,200 people and saw 250 others taken hostage.
The United States in August also designated Palestine Action as a terrorist group. President Donald Trump has described activists who targeted his Turnberry golf resort in Scotland last year as "terrorists".
