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 While the use of the Royal Prerogative for national security reasons is considered outside the scope of the courts, most other uses of the Prerogative are now judicially reviewable in some form. The GCHQ case also confirmed that non-legal conventions might be subject to "legitimate expectation". A convention would not have usually been litigible, and it was necessary for the court to demonstrate that it was in the present case: such a rule had been established in respect of Cabinet conventions in "Attorney General v Jonathan Cape Ltd". Although the court ruled against the union, it was accepted that the