Introduction to judicial review and its scope

Judicial review is the supervisory jurisdiction by which courts control the lawfulness—not the merits—of public power. The distinction is foundational: courts review whether decisions are made lawfully, not whether they are correct (Lord Brightman, Chief Constable of North Wales Police v Evans [1982] 1 WLR 1155). This encompasses three dimensions of scope: (1) amenability (which bodies/decisions are reviewable—statutory, prerogative, and public function bodies per Datafin); (2) standing (who can challenge—those with 'sufficient interest' under s.31(3) SCA 1981); and (3) grounds (Lord Diplock's canonical trilogy in GCHQ: illegality, irrationality, procedural impropriety, plus emerging proportionality). The constitutional justification remains contested between the ultra vires doctrine (review enforces Parliament's implicit intent) and common law constitutionalism (courts independently enforce rule of law principles). Both models coexist uneasily but produce similar outcomes in practice.

Anisminic Ltd v Foreign Compensation Commission [1969] 2 AC 147: Ouster clause stating decisions 'shall not be called in question' did not protect jurisdictional errors, which the House of Lords defined broadly to include virtually any error of law. This entrenched judicial review as constitutionally fundamental—only the clearest language can exclude review, and even then courts resist.

Ridge v Baldwin [1964] AC 40: Natural justice principles apply to administrative decisions affecting rights even without express statutory requirement. This revived procedural fairness beyond quasi-judicial contexts and established the modern duty to act fairly.

*Council of Civil Service Unions v Minister for the Civil Service [1985] AC 374 (GCHQ)*: Lord Diplock's tripartite classification (illegality, irrationality, procedural impropriety) became the canonical framework for grounds of review. Also established that prerogative powers are reviewable in principle, subject to justiciability.

R v Panel on Take-overs and Mergers, ex parte Datafin plc [1987] QB 815: Non-statutory bodies exercising public functions are amenable to review—what matters is the public nature of the power, not its source. This expanded review beyond statutory/prerogative bodies to self-regulatory organisations woven into public regulation.

O'Reilly v Mackman [1983] 2 AC 237: Public law challenges must proceed by judicial review procedure, not ordinary civil proceedings, to prevent evasion of protective features (permission, time limits). Though since relaxed, this established the public/private divide in procedure.

Courts apply a structured analysis: First, amenability—is this a public body/function? Consider statutory underpinning, governmental authority, public interest, whether government would otherwise perform the function (Datafin factors). Second, standing—does the claimant have 'sufficient interest'? This is contextual, considering the applicant's concern, the duty's nature, and whether a more appropriate challenger exists (Fleet Street Casuals). Third, permission stage—is the claim arguable, timely (within 3 months), and not academic/vexatious? Fourth, substantive grounds—apply the GCHQ categories systematically. For each alleged breach, identify which ground applies and test against established standards. Finally, remedies—even if grounds are made out, relief is discretionary; courts may refuse for delay, alternative remedy, or where outcome wouldn't differ (SCA 1981 s.31(6)). Throughout, courts calibrate intensity of review according to subject-matter: minimal scrutiny for policy/resources, heightened for rights/legality.

Confusing review with appeal: Never suggest courts substitute their judgment on the merits—emphasise supervisory jurisdiction and lawfulness/correctness distinction. Oversimplifying ultra vires: The debate is live; present both theories (Wade/Forsyth vs Craig/Laws) with strengths/weaknesses rather than declaring one 'correct'. Ignoring procedural requirements: Always check amenability, standing, and time limits before analysing grounds—many claims fail at these thresholds. Treating non-justiciability as absolute: Post-GCHQ, even prerogative/national security decisions are reviewable for lawfulness; justiciability affects intensity not immunity. Assuming remedy follows unlawfulness: Remedies are discretionary—courts may refuse relief despite proven grounds.