The Civil Service Union challenged a decision to ban trade union membership at GCHQ on national security grounds.

Although this case was mainly concerned with the justiciability of Royal Prerogative powers delegated to the executive, Lord Roskill (obiter) said that powers to dissolve Parliament, appoint ministers, and grant honours ‘as well as others’ were not justiciable.

Among other things, the House of Lords had to decide whether the High Court had the power to issue an injunction against the Crown and, if so, was the Home Secretary, in either their personal or ministerial capacity, in contempt of court for ignoring it.

This case draws attention to the fact that the term ‘the Crown’ is capable of having two meanings, namely, the monarch and the executive, to which the monarch’s powers have been delegated.

The Court of King’s Bench had to decide whether the monarch had any right to take part in the judicial process.

The monarch cannot take part in any criminal or civil action or influence the decision of any court of justice. The monarch cannot issue a warrant of arrest.