From 1764 to 1776, there was a political crisis regarding the authority of the British Parliament over America. Yet the British case for parliamentary sovereignty was not particularly clear, and by 1774, most Americans argued that Parliament had no authority over internal affairs in America. Even English politicians and lawyers, such William Pitt the Elder and Lord Camden, argued that Parliament had no ability to tax the American colonies. In 1776, the American colonies declared their independence and a war of independence ensued, that Britain lost. But what could explain this disagreement over sovereignty? This chapter looks to several factors for explanation. These include the fact of Britain’s uncodified Constitution, which rendered it unclear which laws were in any case ‘constitutional’. There was also disagreement as to how the British Constitution applied in the colonies. Many Americans asserted that only a shared monarch connected American colonies legally to Britain and to each other, and that colonial assemblies were comparable to Parliament. There was, however, no acceptance of this in Britain, where the doctrine of undivided and unlimited sovereignty was increasingly employed by those in power.

The legacy of nineteenth-century constitutionalism hampers the effective realization of democracy in the UK. Bagehot’s eulogizing of the fusion of the executive and legislature now appears to grant far too much power to the government, given the context of parliamentary sovereignty and a ‘first past the post’ electoral system. But democracy is a far richer notion than one which requires merely that power should be exercised by a majority of elected representatives. Democracy also requires that individuals and minorities have certain fundamental protections from majoritarian interests. Democracy in Britain has also been weakened by vagueness as to the role of direct democracy (and how it relates to popular sovereignty) and referendums in the UK. The UK Cabinet Manual (which, absent a codified Constitution, is the closest Britain comes to codifying its constitutional principles) does not specify the role of referendums in British governance, nor suggest that a referendum vote might override other constitutional principles. However, the Brexit referendum, although advisory in status, was nonetheless perceived as binding and implemented. If referendums are to become a more frequent feature of British constitutional practice, there is an urgent need for clear principles regarding their use to be articulated.

The concept of federalism, and examples of federalism, are considered. Although, over 100 years ago, British Imperial federalists argued the empire must ‘federate or disintegrate’, the imperial federation movement did not succeed. Nor did its close relation, the ‘Home Rule All Round’ movement. Instead, the UK has become a devolved State, which transfers power from the centre without relinquishing sovereignty. The main obstacles to federalism in the UK appear to be the ‘England problem’ and parliamentary sovereignty. It has long been recognized that the disproportionate size of one federal unit can destabilize federalism by affecting the capacity of other territorial units to influence central government. However, the main obstacle lies with an insistence on preserving absolute parliamentary sovereignty in the UK. Dicey insisted that ‘limited sovereignty’ was a ‘contradiction in terms’ and that federalism was ‘absolutely foreign to the historical and, so to speak, instinctive policy of English constitutionalists.’ But this chapter argues there is no reason why sovereignty must be understood only as unlimited and indivisible. The obstacle is a lack of political will and not legal impossibility.

Unions take a variety of forms and it is not always clear what species of legal entity one is dealing with. They need not require a unitary State and may exist along a spectrum of State connectivity, from an affiliation of separate States, through to their complete fusion. This chapter examines other Unions – either past, for example Austria-Hungary, or present, such as the USA and EU. The UK Union itself only dates from 1707, is voluntary in nature, and (unlike some Constitutions) there is no legislation prohibiting secession by one part of the UK, nor any constitutional provision asserting and mandating constitutional integrity. This chapter argues it is preferable to understand the UK as a ‘Union State’ – that is, a State where the centre does not directly control every part of the territory – rather than unitary in nature, because there are different constitutional arrangements in different parts of the UK. Unions tend to do better if more elastic and less constraining. But current understandings of UK parliamentary sovereignty make such elasticity very difficult for the UK Union. The doctrine of unlimited sovereignty places an almost insurmountable barrier to resolution of issues threatening the Union today, particularly those of devolution.

There was no legal definition of the British Empire and it possessed no explicit constitutional meaning. The empire was diverse and incoherent and terminology was not very clear. The terms ‘colony’, ‘dominion’, ‘possession’, ‘plantation’, and other expressions were used in different ways at different times. Indeed, an anti-formalist attitude tended to prevail – often eschewing formal law in favour of informal assurances, customs, and conventions. There was no attempt to establish a uniform legal code. And the sovereignty of the Parliament in London was only one of many types of sovereignty that existed. Much of the British Empire lent itself to a more pluralistic type of sovereignty – one that was divided, shared and indeterminate. Indeed, it was likely that power was the only unifying factor underlying the empire, aided by British naval supremacy, and the fact that, in the nineteenth century, global communications were predominantly in British hands. However, that power could not be derived from a unified, coherent account of legal and political sovereignty. And power by itself lacks legitimacy – it must be validated by something else – which is where sovereignty becomes relevant, in providing that grounding. Yet, the claims of sovereignty made by the empire were often mutually self-contradictory.

The legal and constitutional relationship between Ireland and England (and latterly Britain) was unclear for many centuries. Although Ireland enjoyed a good deal of legislative sovereignty under Grattan’s Parliament from 1782, the Acts of Union in 1801 set up direct rule from Westminster. During the nineteenth century, there was a campaign and draft legislation for Irish Home Rule (which Dicey, an ardent unionist, vehemently opposed). This campaign is worth reconsidering in the Brexit/Scottish independence context, given the varied legal and constitutional arrangements that were explored and vigorously debated. However, Home Rule never came about, rendered pointless by subsequent events. Since the Belfast/Good Friday Agreement and devolution in 1998, Northern Ireland has a had a variegated but pragmatic settlement of consociation and compromise quite different from the traditional British constitutional settlement. The EU has played its role in the peace process, providing structures for its continuation. Brexit now presents considerable challenges for Northern Ireland and the Republic.

The union of Scotland and England was the founding act of the UK in 1707, and consensually agreed between two sovereign parties. Scotland was never a colony of England and post-union retained considerable autonomy, including its distinct and separate legal and education systems and Church. As a result of the 1707 union, the UK Parliament (which was not simply the English Parliament enlarged) came into being. The doctrine of unlimited parliamentary sovereignty is not accepted by everyone in Scotland, where there exists an alternative Scottish tradition of popular sovereignty, and the belief that Scotland’s place in the UK Union rests on its consent. Since devolution in 1998, Scotland has developed some progressive constitutional forms, as well as more pro-European inclinations that challenge the unitary constitutional approaches of London. Brexit, however, has placed the UK union under strain, and there have been demands for a second Scottish Independence referendum. Surprisingly, despite the threat of Scottish independence, there has been little debate about what the ‘Union’ or ‘Britain’ is or should be.

This book provides a critical analysis of Brexit, placing it in the broader context of the historical development of the British Constitution and earlier disputes as to the meaning of statehood, sovereignty, and territorial boundaries. Some of the greatest challenges posed by the UK’s withdrawal from the EU are those it places on the British Constitution, which is already ‘unsettled’ and under strain. This book investigates this impact, but also uniquely locates Brexit in the broader context of historically significant British ‘acts of union or disunion’ – such as the loss of former US colonies and British Empire, and the place of Scotland and Ireland in the Union. These precedents help us understand how a British constitutional identity has been shaped or dismantled by legal concepts of union or sovereignty.

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 book provides a critical analysis of Brexit, placing it in the broader context of the historical development of the British Constitution and earlier disputes as to the meaning of statehood, sovereignty, and territorial boundaries. Some of the greatest challenges posed by the UK’s withdrawal from the EU are those it places on the British Constitution, which is already ‘unsettled’ and under strain. This book investigates this impact, but also uniquely locates Brexit in the broader context of historically significant British ‘acts of union or disunion’ – such as the loss of former US colonies and British Empire, and the place of Scotland and Ireland in the Union. These precedents help us understand how a British constitutional identity has been shaped or dismantled by legal concepts of union or sovereignty.

Lord Bingham noted that the Common Law was not an isolated island, and that English law had always shown a receptiveness to ‘the experience and learning of others’. Brexit might appear to have set back that optimism. However, British relations with continental Europe are deep and historical. British lawyers played a very strong role in the creation and founding of the European Convention on Human Rights, so ECHR rights (now incorporated in the Human Rights Act) are not alien, foreign devices. Furthermore, Britain was not forced into EEC membership, but joined voluntarily, persisting after its first two applications were rejected by General de Gaulle, because it perceived that it would be socially and economically enriched by such membership – a perception that turned out to be accurate. EU membership also provided an external support system for UK devolution, facilitating common approaches within the UK and conciliation between the UK and Ireland. The EU and ECHR provided external guarantees and entrenchment of human rights, many of which are now at risk post-Brexit.

Human rights have had a fragile status in Britain, given the overpowering doctrine of parliamentary sovereignty, which has enabled a parliamentary majority to achieve any policy in the absence of entrenched constitutional protections. Plans to repeal the 1998 Human Rights Act are evidence of this. Dicey wrote that parliamentary sovereignty was tempered by the rule of law in the UK, but it is unclear from his work how the rule of law could operate to override the will of a despotic parliamentary majority. Brexit adds to this precarity, by removing EU human rights protection from UK law (which had something close to an entrenched status, while the UK was an EU member). This calculated deletion of fundamental rights – involved in the deliberate exclusion of the EU Charter of Fundamental Rights from UK law post-Brexit – is almost unparalleled in the Western world (although perhaps the US Supreme Court’s Dobbs decision, which removed the protected status of the right to abortion from US constitutional law, comes close, at least for that right).