Council of Civil Service Unions v Minister for the Civil Service (GCHQ)
[1985] AC 374
Ratio Decidendi
The exercise of prerogative powers is in principle subject to judicial review. The three heads of judicial review are illegality, irrationality, and procedural impropriety.
Facts
The Minister for the Civil Service (the Prime Minister) issued an instruction banning trade union membership at GCHQ on national security grounds without prior consultation.
Judgment Summary
The House of Lords held that prerogative powers are reviewable, but the ban was justified on national security grounds. Lord Diplock articulated the three grounds of judicial review: illegality, irrationality, and procedural impropriety.
Key Quotes
"Judicial review has I think developed to a stage today when one can conveniently classify under three heads the grounds upon which administrative action is subject to control by judicial review."
— Lord Diplock
Subsequent Treatment
Lord Diplock's three heads remain the orthodox classification of grounds for judicial review.