1. What administrative law is

The purpose

Control of power: Modern government acts through a vast number of decisions: licences, permits, benefits, dismissals, planning and tax. Administrative law makes sure each decision stays within the legal power that authorises it.

Protection of the individual: It gives the person affected a way to challenge a decision, usually in the High Court, and to have an unlawful decision set aside.

Good administration: It also encourages officials to act fairly and give reasons, which improves the quality of decisions.

Its link with constitutional law

The rule of law: Administrative law is the rule of law in daily practice. As Entick v Carrington showed, an official needs legal authority for what he does.

The separation of powers: The courts do not take the decision for the official. They review whether it was lawfully made. Review is about legality, not about the merits.

Review and appeal

Appeal: An appeal exists only where a statute gives one. The appeal body can usually look again at the merits and substitute its own decision.

Judicial review: Review exists at common law and through the supervisory jurisdiction of the superior courts. The court asks whether the decision-maker acted within its powers and fairly. If not, the decision is quashed and usually sent back to be made again.

The grounds in outline

Three heads: In the GCHQ case Lord Diplock grouped the grounds of review under illegality, irrationality and procedural impropriety, and suggested that proportionality might later be added. The chapters that follow take each in turn.