Judicial review is a legal process through which a court examines the lawfulness of governmental or public authority action. The precise meaning varies between legal systems. In England and Wales, judicial review is principally concerned with whether a public body acted lawfully, within its powers and according to required procedures.
The Courts and Tribunals Judiciary describes it as a proceeding in which a judge reviews the lawfulness of a decision or action made by a public body and emphasises that it generally challenges the way a decision was made rather than simply asking whether the court considers the underlying outcome correct. In the United States, judicial review commonly refers to the authority of courts to assess governmental action, including legislative and executive action, against the Constitution and, where unconstitutional, to invalidate it. These are related but institutionally distinct uses of the same term.
In UK public law, judicial review is not normally an appeal on the merits. The court does not simply replace an administrative decision maker's judgment with its own preferred decision. Instead, the court examines whether the public authority exercised its power lawfully. Issues can include whether the authority acted within its statutory powers, followed required procedures, considered legally relevant matters, avoided legally irrelevant considerations, respected applicable rights and complied with principles of fairness.
If a decision is unlawful, the court can grant an appropriate remedy, potentially requiring the public body to reconsider the matter lawfully. The public body may in some circumstances reach the same substantive outcome after following the correct legal process. This distinction between legality and merits is central to understanding judicial review in the UK.
In the United States, judicial review has a broader constitutional dimension because courts can determine whether legislative or executive action conflicts with the Constitution. The US Supreme Court's power of constitutional judicial review was established in the landmark case Marbury v Madison in 1803, although the underlying idea of courts enforcing higher law existed earlier. The Supreme Court explains that judicial review allows it to determine whether legislation or executive action conflicts with constitutional requirements. This form of review places constitutional limits on the other branches of government because ordinary legislation and executive action cannot lawfully override the Constitution. The American model therefore illustrates judicial review as constitutional supremacy enforced through judicial adjudication.
Judicial review depends on jurisdiction, standing, procedural rules and the legal status of the challenged action. A court cannot review every governmental decision simply because someone disagrees with it. The claimant ordinarily needs a recognised legal basis for bringing the case, and the challenged decision must fall within the court's jurisdiction. Courts can also impose procedural requirements such as time limits, exhaustion of alternative remedies or restrictions on who may bring particular claims.
In public law, the court must determine whether the defendant is a public body or is exercising a function subject to judicial supervision. In constitutional review, the court must determine whether the constitutional question falls within its authority. These jurisdictional constraints prevent judicial review from becoming an unlimited general power to supervise every governmental preference.
Judicial review can protect individuals and institutions against unlawful exercises of public power. Examples can include challenges to regulatory decisions, immigration decisions, local authority decisions, welfare decisions, prisoner rights decisions and other exercises of administrative authority. The UK judiciary identifies these types of decisions as examples of matters that can fall within judicial review. The process can require public bodies to reconsider decisions or comply with legal requirements. Constitutional review can additionally protect constitutional rights and structural limits on governmental power. In either model, the significance of review lies in the principle that public authority must operate within legally defined limits rather than possessing unrestricted discretion.
Judicial review should be distinguished from an ordinary appeal. An appeal generally asks a higher court to determine whether a lower court made an error of law, fact or procedure according to the applicable appellate rules. Judicial review of administrative action instead examines the legality of action taken by a public authority. The two processes can overlap in practical consequences but are conceptually different.
The UK judiciary specifically states that if a person simply argues that a decision was incorrect, judicial review may not be the appropriate remedy and that an appeal may be available instead. This distinction is important because judicial review is designed to control lawful exercise of public power, not to create a general judicial entitlement to substitute a court's preferred administrative policy for that of the legally authorised decision maker.
Judicial review has an important constitutional dimension because it embodies the proposition that governmental authority is legally limited. In systems of constitutional supremacy, courts can enforce constitutional constraints against legislation and executive action. In systems of parliamentary sovereignty, courts may instead focus heavily on whether administrative authorities have complied with statutes and common law principles while lacking a general power to invalidate primary legislation. The United Kingdom and United States therefore illustrate different forms of judicial review. Neither model should be treated as universally representative. The institutional design of review depends on the constitution, legislative framework, judicial hierarchy, rights protections and legal tradition of each jurisdiction.
Judicial review consequently means different things in different legal contexts, and accurate analysis requires identifying which model is being discussed. At its broadest, it refers to judicial scrutiny of government or public authority action for legality. In UK public law it is principally concerned with the lawfulness of public decision making, while in the United States it also denotes constitutional review through which courts may invalidate legislation or executive action inconsistent with the Constitution. In both settings, judicial review connects judicial authority with the rule of law by providing a legal mechanism for challenging exercises of public power that exceed or violate the limits imposed by the relevant legal order.
