Abstract This chapter examines the circumstances in which a court may, or must, refuse a final public law remedy even after finding that a decision or action was unlawful. It begins with the statutory ‘no substantial difference’ test under s 31(2A) of the Senior Courts Act 1981, which obliges the court to withhold a remedy where it is highly likely the outcome for the claimant would not have been substantially different, subject to an exceptional public interest exception. The chapter then analyses the wide range of discretionary grounds on which remedies may be refused, grouped broadly into claimant-related factors (such as prematurity, delay, conduct, standing, or failure to exhaust alternatives), considerations relating to third parties or administration (including hardship, prejudice, and detriment to good administration), and issues concerning the value or purpose of the remedy (academic or hypothetical claims). Throughout, the importance of principled, non-arbitrary discretion is emphasized to safeguard the rule of law.
Abstract This chapter examines the circumstances in which a public body acts outside the scope of its powers or duties. It explains that illegality arises when a body misunderstands or misapplies the law governing its authority, and notes the historical but now largely obsolete distinction between jurisdictional and non-jurisdictional errors. It identifies key situations in which action exceeds lawful authority, including erroneous interpretation of statutory provisions, mistakes about statutory preconditions, acting without the factual basis required for authority, and revisiting decisions when functus officio. It also addresses limits on the jurisdiction of inferior courts and tribunals, the narrow exception for officers and judges acting de facto, and the principle that unlawful acts cannot normally be ratified. Finally, it outlines the routes for challenging decisions taken without lawful authority and the procedural considerations that may arise.
Abstract Chapter 12 explains the legal sources of powers and duties exercised by public bodies and the principles used to determine their limits. Statutory bodies possess only those powers expressly or implicitly conferred by legislation, while ministers may additionally rely on prerogative and certain common law powers. The chapter sets out how to identify whether legislation confers a power or imposes a duty, noting that permissive and mandatory wording is not determinative and that context may require a permissive power to be treated as a mandatory duty. It also discusses ‘target duties’, which require reasonable efforts toward broad public objectives but are generally unenforceable by individuals. To determine the scope of statutory powers, the courts apply principles of interpretation, including presumptions against interfering with constitutional rights, authorizing taxation, allowing delegated legislation to defeat statutory rights, retrospectivity, uncertainty, or enabling benefit from serious crime. Public bodies may have implied incidental powers, but such implications must align with the statutory scheme. The chapter concludes with an overview of prerogative powers, their displacement by statute, and the limited but recognized existence of residual common law powers, all ultimately subject to judicial determination of their scope and lawfulness.
