High Quality Content by WIKIPEDIA articles! Council of Civil Service Unions v Minister for the Civil Service AC 374, commonly known as the GCHQ case, was an English administrative law which held that the Royal Prerogative was subject to judicial review. In 1984 the British government under Margaret Thatcher decided that employees of the Government Communications Headquarters (GCHQ) would not be allowed to join a trade union for national security reasons. This was enforced through an Order in Council, an exercise of the Royal Prerogative. The Council of Civil Service Unions chose to bring this matter to court through judicial review, first to the High Court of Justice, which ruled the Order in Council was invalid. The case then went to the Court of Appeal, which decided that the national security issues trumped any problems of propriety.