## Facts

- The Prime Minister, Margaret Thatcher, used prerogative powers to ban employees at the Government Communications Headquarters (GCHQ) from joining trade unions without consultation.
- This decision was justified on the grounds of national security.
- Trade unions representing GCHQ staff challenged the government’s failure to consult prior to implementing the ban, asserting it contravened prior agreements and recognized rights.

## Issues

1. Whether prerogative powers exercised by the government are subject to judicial review.
2. Whether the invocation of national security can exempt the exercise of prerogative powers from judicial scrutiny.
3. Whether the government’s failure to consult GCHQ staff, in line with previous practice, rendered the decision unlawful.

## Decision

- The House of Lords held that prerogative powers are, in principle, subject to judicial review.
- Prerogative powers may be reviewed by courts unless their subject matter—such as national security, treaties, defense, pardons, honors, dissolving Parliament, or ministerial appointments—places them outside the court’s remit.
- In this case, evidence concerning security threats justified the lack of consultation, and the national security context exempted the decision from review.
- The government’s action was therefore not unlawful given the overriding consideration of national security.

## Legal Principles

- Prerogative powers, historically immune from legal challenge, are reviewable by courts except when concerns fall under specified exemptions, such as national security.
- Judicial review of prerogative powers ensures government actions comply with legal norms but recognizes limits where sensitive state interests are at stake.
- Courts must defer to the executive in evaluating threats to national security, maintaining a balance between legal accountability and public welfare.
- The case clarified separation of powers and influenced subsequent administrative law decisions involving prerogative authority.

## Conclusion

The decision in CCSU v Minister for the Civil Service marked a fundamental shift by subjecting many prerogative powers to judicial review, while delineating areas, such as national security, where deference to executive judgment is required. The case remains a landmark in modern administrative law.

Council of Civil Service Unions v Minister for the Civil Service [1985] AC 374 (HL)