Council of Civil Service Unions v Minister for the Civil Service (GCHQ) is a British intelligence agency that provides signals intelligence to the British government and armed forces. Prior to 1983 its existence was not acknowledged, despite the fact that it openly recruited graduates. Following a spy scandal in 1983, the organisation became known to the public, and the government of Margaret Thatcher decided a year later that employees would not be allowed to join a trade union for national security reasons. The Minister for the Civil Service is a position held "ex officio" by the Prime Minister. This was done through an Order in Council, an exercise of the Royal
Council of Civil Service Unions v Minister for the Civil Service Council of Civil Service Unions v Minister for the Civil Service Council of Civil Service Unions v Minister for the Civil Service [1984] UKHL 9, or the "GCHQ case", is a UK constitutional law and UK labour law case that held the Royal Prerogative was subject to judicial review. In 1984, the government of Margaret Thatcher banned employees of the Government Communications Headquarters (GCHQ) from joining any trade union for "national security" reasons by an Order in Council using the Royal Prerogative. The Council of Civil Service Unions claimed in judicial review that defeated their legitimate expectations, to collectively bargain