NICOSIA, Cyprus — Cypriots who fought against British colonial rule in the 1950s plan to sue the U.K. government for torture they allegedly suffered at the hands of British authorities while in custody, an official said Wednesday.

Thassos Sophocleous, president of an organization representing former Cypriot fighters, said the British law firm K.J. Conroy & Co. is now gathering information from them to build a case following this month’s landmark ruling from Britain’s High Court, which found that three Kenyans tortured during a rebellion against British colonial rule can seek compensation....