New Delhi, Feb. 13 -- A British government ban on Palestine Action under anti-terror laws was unlawful, London judges ruled, throwing hundreds of prosecutions against supporters of the group into doubt.

The High Court moved to quash the UK ban on Friday, declaring it "disproportionate," in an embarrassing reversal for Prime Minister Keir Starmer's government. The judges declared that Palestine Action would remain proscribed as a terrorist organization "until further order of the court," giving the government time to appeal.

The UK Home Office banned Palestine Action in July last year in a contentious move after the group said it had damaged two military aircraft. Supporters and human rights activists criticized the move for its overreac...