Sovereignty is obviously key in the Brexit context, and in many ways lies at the core of this book’s argument – a main part of which is that Britain has never been able to justify its assertion of unlimited parliamentary sovereignty. This book endorses the view that the doctrine of parliamentary sovereignty no longer carries the weight that Dicey accorded it, nor should it. Indeed Dicey was himself inconsistent, and, in his energetic opposition to Irish Home Rule, was prepared to depart from the application of parliamentary sovereignty. And in any case, Dicey’s theory is not watertight historically, and Westminster sovereignty is also territorially challenged. However, it might be argued that EU membership posed the greatest challenge to UK parliamentary sovereignty. However, Britain never lost its external sovereignty (i.e. what is frequently described as ‘national’ sovereignty, whereby a country is sovereign and recognized as independent by the international community) as Britain voluntarily joined the EEC, and also voluntarily exited, with Brexit. But Parliament did constrain its own sovereignty through the ECA 1972, and although that Act has now been repealed by Brexit, there is no reason why Parliament should not place further constraints on its own sovereignty in future.

This chapter examines the power of the legislature to have ’the last word’ under section 33 of the Canadian Charter of Rights, and the UK Human Rights Act 1998. In both cases, the democratically elected legislature is empowered to legislate notwithstanding rights. Whilst both of these provisions have been hailed as the lynchpin of a New Commonwealth model of constitutionalism, or as an instance of weak-form review, this chapter observes that they have hardly ever been used. The task of the chapter, then, is to examine and explain ’the underuse of the override’. Departing from the dominant narrative that the legislature wanted to use the override but was thwarted by exogenous political costs, this chapter argues that the rare use of the override was part of the original design of both systems from the outset. Instead of being a tragic thwarting of democratic dialogue, or an unfortunate atrophy of constitutional powers, rare use of the override was a feature, not a bug in both systems. Supplementing the historical narrative with normative argument, the chapter defends the rare use of the override as a vindication of the collaborative constitutional ideal.

The legislature has been one of the central institutions in the UK’s constitutional history, a forum in which major political events occurred and decisions were taken. The legislature projects constitutional values: its practice is based on the significance of representation, accountability, transparency, deliberation, contestation, and collective action. Moreover, the UK Parliament is the focus of the fundamental norm around which the constitution is structured.

The British Constitution possesses many distinctive features: from its uncodified character and lack of entrenchment to the status as ordinary statutes rather than ‘higher’ law of those written rules that comprise it. However, all these features can be regarded as manifestations of its most distinguishing characteristic – its quality as a predominantly ‘political’ rather than a ‘legal’ constitution.1 Whereas codification, and those other features that the British Constitution notoriously lacks, comprise essential elements of a legal form of constitutionalism, their absence has traditionally been deemed necessary for the integrity of the UK’s political constitution.

By the early twentieth century, democracy was in the ascendant. Not all observers and practitioners were enthusiastic about this development. But, whether favourable towards it or not, they came to accept the predominance of the concept that the people were the ultimate source of political authority.1 An example of a grudging acknowledgement that confirms the strength of the conceptual transition that had occurred came from the constitutional historian, William Sharp McKechnie. He observed in his 1912 work of contemporary analysis The New Democracy and the Constitution that the public pronouncements of politicians suggested ‘the triumph of Democracy in Great Britain is now assured’ McKechnie noted a tendency as common to ‘Conservatives and Liberals as’ as it was among ‘Socialists and Labour leaders’ to display ‘[a] fervent and almost servile eagerness to interpret and to execute “the people’s will”’.2

This chapter explores the normative foundations of judicial review by rounding back on the concept of office. Judicial review exists to ensure that repositories of official power act only within the scope of the powers reposed in them. Official ‘power’ is inherently limited in virtue of being translated into official ‘powers’ (i.e., vires) that are implicitly capable of judicial interpretation and enforcement. The same applies for the constrains (i.e., rules of conduct) that operate on the manner, form, and purpose of their exercise. This gives rise to a concept of the rule of law as the rule of officials acting lawfully, which is a powerful expression of the ‘rule of law, not of men’ strand of thinking that traces back to Bracton at least. Office provides a superior point of departure than the radical English notion of parliamentary soveriegnty. This makes an appropriate concept of ‘public trust’ or ‘public fiduciary law’ the best expression of the conceptual and normative basis of judicial review. Far from being a slipshod translant of private law fiduciary remedies into public law, the emerging idea of ‘public fiduciary law’ is an apt expression of the deeper logic of office.

This chapter examines the doctrine of parliamentary sovereignty, the commonly used shorthand for the legal supremacy attributed to Acts of Parliament within the hierarchy of norms in the UK’s constitutional system. The characteristics of the doctrine are examined, alongside its historical origins and the crucial distinction between the idea of legal sovereignty and that of political or popular sovereignty. We then go on to examine potential limitations on Parliament’s legislative power, before examining and assessing contemporary challenges to the orthodox model of legal sovereignty. While the doctrine of legal sovereignty undoubtedly forms the backbone of the UK’s Constitution, it should be considered alongside the principle of the rule of law and – to a lesser extent – that of separation of powers. Parliamentary sovereignty is also closely aligned with the idea of political accountability. Each of these additional constitutional principles is considered in the chapters which follow.

The Brexit process has been characterised by hyper-litigation – an unprecedented level of strategic litigation brought to influence the process, substance and/or the politics of the UK’s departure from the European Union. Although strategic litigation is by no means unknown in the UK context, we argue that the volume, and unusual degree of success, of Brexit-related litigation may represent a further step change in the use of strategic litigation in the UK constitutional context.

In this chapter, we catalogue more than 50 instances of Brexit-related strategic litigation in the UK, EU and other European courts, up until the date of the UK’s departure from the EU on 31 January 2020. We analyse, first, by whom, about what, and with what aims cases were brought. Secondly, we discuss the impacts of the litigation, both in legal terms – seeking to identify why some cases succeeded where others did not – and in terms of their broader political effects. Thirdly, we try to account for hyper-litigation, identifying the various factors encouraging resort to the courts. Finally, we consider the likely long-term impacts of Brexit-related strategic litigation, and the potential for backlash against politically-motivated litigation by both political actors and the courts themselves.

This chapter sets out and explains the key principles and values of the UK constitution - and of constitutionalism more generally. It explains parliamentary sovereignty, the rule of law, democracy and the separation of powers. It provides contemporary examples of the application of these values and principles , including the impact of referendums and of the two groundbreaking Miller decisions - known as the Brexit and the prorogation cases.

This chapter provides an up-to-date account of the evolving history of devolution in the UK. In particular, it explains the impact of the independence referendum in Scotland, the move to devomax and the possibility of a second independence referendum. It provides an up-to-date account of further devolution to Wales. It also provides an account of the failure of devolution in Northern Ireland from 2017-20, looking at the governance of Northern Ireland by civil servants. It also provides a new analysis of the impact of devolution on parliamentary sovereignty and the impact of Brexit on devolution.

The chapter examines the impact of Brexit on transnational solidarity. It explains how Brexit was triggered, in part, by concerns as to the impact of EU membership, both in terms of the UK’s identity as a member of the EU and the impact of migration. This negative impact on transnational solidarity will only continue post Brexit, particularly if the UK were to leave the EU with no deal concerning its future relationship. Some of these issues would be mitigated were the UK to leave under the terms of the current Withdrawal Agreement. Nevertheless, the chapter argues that some of the benefits of EU membership will continue post Brexit, particularly as concerns the impact of the UK’s membership of the EU on the UK constitution.

This chapter considers the idea of constitutional identity as it pertains to the UK, viewed from the perspective of EU-UK relations. The analysis begins by consideration of the conceptual frame within which the relationship between UK and EU law evolved, and more especially the way in which supremacy was conceived in EU law and UK law, respectively. The discussion thereafter shifts to a more general consideration of the idea of constitutional identity in the UK. While the language of constitutional identity is not commonly used in judicial discourse, there are nonetheless a number of precepts that are central to the identity of the UK constitutional order. These include parliamentary sovereignty, constitutional statutes and the principle of legality, the rule of law, and devolution. The analysis then shifts to the consequences of a clash between EU law and UK law that impacts on one of the preceding UK constitutional precepts. These consequences may be interpretive or substantive in nature, and they are examined in turn. Brexit, however, means that it is unlikely that the issues raised in the last section of the chapter will be tested.