Council of Civil Service Unions v Minister for the Civil Service [1984] UKHL 9; [1985] AC 374
Facts
The government changed the employment conditions of staff at the Government Communications Headquarters, preventing membership of national trade unions. The instruction was made through prerogative machinery governing the civil service. Contrary to established practice, the unions were not consulted before the change. The government relied on national security and concern about disruption to intelligence work. The unions sought judicial review, arguing that the established consultation practice should have been respected. The litigation required the House of Lords to consider both the reviewability of prerogative powers and the effect of the security justification on procedural fairness.
Legal Issue
Whether removing the employees’ trade-union rights without consultation breached procedural legitimate expectation, and whether the government’s national-security justification defeated the challenge to that decision.
Held
The House of Lords dismissed the appeal while accepting that prerogative action could be subject to judicial review. Reviewability depended on the nature of the power rather than its prerogative source alone. The unions had a legitimate expectation of consultation arising from established practice, but the national-security considerations established in this case justified dispensing with it. Lord Diplock described illegality, irrationality and procedural impropriety as the recognised grounds of review. The outcome did not mean that invoking national security automatically defeats a claim or that no expectation had arisen. It reflected the evidence and the respective institutional roles in assessing this particular change to intelligence-service employment conditions.
⭐ Legal Principle
Prerogative powers may be judicially reviewable according to their subject matter. In GCHQ, established practice created a legitimate expectation of consultation, but an adequately established national-security justification permitted departure from it. The existence of an expectation does not guarantee its enforcement in every circumstance.
Significance
GCHQ rejects immunity from review merely because a power originates in the prerogative. It also shows how a legitimate expectation of consultation can yield to an adequately established overriding interest. Lord Diplock's classification of illegality, irrationality and procedural impropriety became a standard teaching framework. The unions' expectation arose from past practice, but national-security evidence justified departing from it. The case therefore separates three questions: whether review is available, whether an expectation exists and whether the circumstances justify frustrating that expectation.
Common exam questions about this case
Were prerogative powers automatically outside judicial review?
No. The House of Lords held that the source of a power did not by itself determine reviewability. Its subject matter and suitability for judicial assessment mattered. That principle allowed review of prerogative action in appropriate cases without asserting that courts should decide every question of foreign affairs or national security.
Did the unions have a legitimate expectation of consultation?
Yes. Established practice supported an expectation that they would be consulted about changes affecting their members. Their claim nevertheless failed because the national-security justification permitted departure from that practice. The case should not be described as finding that the expectation never arose at all.
What were Lord Diplock’s three grounds?
He identified illegality, irrationality and procedural impropriety as established grounds of review. The categories address legal authority, the rationality of the decision and the fairness or lawfulness of the process. He did not present the list as permanently closed or decide that proportionality was already a universal common law ground.