This chapter reviews the modern cases on the ‘third source’ in England and Wales and around the Commonwealth. This review illustrates that the law is fundamentally uncertain on the legal nature and exact provenance of these powers within each jurisdiction surveyed. It also illustrates that basic questions of legal theory relating to official empowerment and official action are unavoidable in the context of non-statutory executive powers. This demonstrates the gap between theory and practice in a specific context and justifies the need for the basic and wide-ranging interrogation of the law of judicial review undertaken in the book.

This chapter sets out the taxonomy of non-statutory executive powers ultimately adopted. It is a very simple taxonomy that draws a fundamental distinction between statutory and non-statutory executive powers but no distinctions for the purposes of judicial review between non-statutory executive powers associated with the Royal Prerogative and those that are more mundane, and appear to be nothing more than the ‘residual liberties’ of the Crown as a legal person. Once the logic of office, official empowerment, and official action is adopted as a premise, the idea of the ‘third source’ as generally articulated simply falls away. While the distinction may be interesting or useful in a historical sense, it is of no relevance to the ‘how’ or ‘why’ of judicial review.

This chapter explores the different ways of approaching judicial review, and makes some initial criticisms of the historical ‘ultra vires debate’ of the 1990s and 2000s. It argues for a return to the concept of jurisdiction (and jurisdictional error) as a central category of the law, and for a focus on non-statutory executive powers as a primary case for and from which to build a theory of the supervisory jurisdiction. While legislative intention is important, wherever it is relevant, it is not relevant where the official powers in question obviously derive from rules of competence outside of legislation. Further, common law rules of conduct are always central to judicial review in the context of statutory grants of power. This insight is conducive to a simpler and more powerful conception of judicial review based around a common law doctrine of ultra vires.

This chapter provides some more detail on the rules of competence and rules of conduct that empower officials to act as such and constrain the scope of their action. The logic of empowerment, and the fundamental distinction between ability and permission, provides a profound insight into the two traditional ‘limbs’ of the ultra vires rule – the ‘narrow’ limb concerned with competence, jurisdiction, or vires in the strict sense, and the ‘broad limb’ concerned with the manner, form, and purpose of an exercise of a competence that the official clearly does have. Not only does this provide a simple and powerful explanation for the ultra vires review of non-statutory executive powers; it provides the foundation for a general theory of judicial review based in the courts’ inherent (common law) jurisdiction to police the bounds of, and constraints upon, officials’ vires – whether statutory or non-statutory.

This chapter introduces the problem of official action beyond statute as a central concern to public law theory. It reviews the most important classical accounts of the Royal Prerogative and the modern notion of a ‘third source’ of executive power besides statute and prerogative. It also introduces a major them in the book, namely the concept of ‘official power’ as a set of ‘legal powers’ and uses this critically to assess common misconceptions about the nature of official action beyond statute – particularly conceptions of the third source as a set of ‘residual liberties’ inuring in the Crown in common with private individuals.