LONDON — Britain’s High Court ruled Friday that the government acted unlawfully when it designated the pro-Palestinian protest group Palestine Action as a terrorist organization, but the ban will remain in place while the government appeals.

Judges Victoria Sharp, Jonathan Swift and Karen Steyn said the “nature and scale” of the group’s activities did not reach the “level, scale and persistence” required to justify proscription under terrorism laws. The court found the decision to outlaw the group was “disproportionate.”

The government last year added Palestine Action to the list of banned terrorist organizations, placing it alongside groups such as al-Qaida and Hamas. Membership in or public support for a proscribed organization carries a maximum sentence of 14 years in prison.

Home Secretary Shabana Mahmood said she was disappointed with the ruling and intends to challenge it in the Court of Appeal, rejecting the notion that banning the group was excessive.

Palestine Action co-founder Huda Ammori called the decision “a monumental victory” for free speech and protest rights.

The government moved to ban the group after activists broke into a Royal Air Force base in June, spraying red paint into the engines of two tanker aircraft and causing additional damage with crowbars. Officials said the actions caused millions of pounds in damage and posed risks to national security.

The group, founded in 2020, has staged direct-action protests targeting military and industrial sites, including facilities linked to Israeli defense contractor Elbit Systems UK.

Supporters and civil liberties groups argue that criminal laws are sufficient to prosecute unlawful acts and that banning the organization infringes on freedom of expression and the right to protest.

In their ruling, the judges said that although a small number of the group’s actions could amount to terrorist activity, existing criminal statutes provide the tools needed to pursue charges without resorting to proscription.