Grounds of Judicial Review — illegality, irrationality, procedural impropriety, proportionality

Judicial review is the High Court’s supervisory jurisdiction over public bodies. A claimant cannot use it to argue the merits of a decision — only to challenge how the decision was made. Lord Diplock’s tripartite framework in CCSU v Minister for the Civil Service [1985] AC 374 remains the spine of the modern law: illegality, irrationality, procedural impropriety. Modern courts add proportionality where the case engages EU-derived rights or the Human Rights Act 1998.

1. Illegality. The decision-maker has misunderstood or misapplied the law. Sub-grounds include acting ultra vires the enabling statute (Attorney General v Fulham Corporation [1921] 1 Ch 440), taking irrelevant considerations into account or ignoring relevant ones (Padfield v Minister of Agriculture [1968] AC 997), improper purpose (Padfield again, Wheeler v Leicester CC [1985] AC 1054), fettering discretion (British Oxygen Co v Minister of Technology [1971] AC 610), and unlawful delegation (Carltona Ltd v Commissioners of Works [1943] 2 All ER 560 recognises permissible internal delegation; the limit is unlawful sub-delegation outside the department).

2. Irrationality (Wednesbury). A decision so unreasonable that no reasonable authority could ever have come to it (Associated Provincial Picture Houses v Wednesbury Corporation [1948] 1 KB 223). A high bar by design — courts are not substituting their own judgment for the decision-maker’s. R (Daly) v SSHD [2001] UKHL 26 confirms the standard becomes more searching where fundamental rights are engaged.

3. Procedural impropriety. Two limbs: (a) statutory procedural requirements not followed, and (b) breach of common-law natural justice — the right to a fair hearing (audi alteram partem) and the rule against bias (nemo iudex in causa sua). Leading cases: Ridge v Baldwin [1964] AC 40; R v Bow Street Metropolitan Stipendiary Magistrate, ex parte Pinochet (No 2) [1999] UKHL 1 on apparent bias; Porter v Magill [2001] UKHL 67 on the modern test (would the fair-minded and informed observer conclude there was a real possibility of bias?).

4. Proportionality. A four-stage test (R (Daly) v SSHD [2001] UKHL 26; Bank Mellat v HM Treasury (No 2) [2013] UKSC 39): (i) is the objective sufficiently important to justify limiting the right? (ii) is the measure rationally connected to the objective? (iii) could a less intrusive measure have been used? (iv) does the measure strike a fair balance between rights and objectives? Used in HRA cases and (post-Brexit) where retained EU principles continue to apply.

Standing. Claimant must have locus standi— sufficient interest in the matter (R v Inland Revenue Commissioners, ex parte National Federation of Self-Employed and Small Businesses Ltd [1982] AC 617). Public-interest claimants have been recognised liberally: R (Greenpeace) v Secretary of State for the Environment [2007]; R (Privacy International) v IPT [2019] UKSC 22.

Remedies.Quashing order, mandatory order, prohibiting order, declaration, injunction, damages (only where the cause of action would otherwise lie). All discretionary — courts may refuse relief if it would serve no useful purpose or if the claim is brought out of time (CPR Pt 54 requires promptness; in any event within 3 months of the decision).

Exam approach.Identify the public-law decision being challenged. Run through each ground in turn. State the test, cite the leading case, apply to facts. For HRA cases, run proportionality alongside illegality. Don’t conflate substantive merits with procedural grounds.

Pair with our UK law glossary for definitions of ultra vires, locus standi, and Wednesbury, and our case library for full briefs of the cases referenced above.