The United Kingdom (UK) and what is now the European Union (EU) were intertwined for nearly half a century. Consequently, Brexit means more than the UK removing itself from the EU. It involves extracting the EU from the UK. The four years after the EU referendum of 23 June 2016 and the political turbulence that followed in the implementation of Brexit, have created uncertainties about the cohesion of the UK and even its continued existence. There have been a variety of apparently discrete disruptions: threats to the Belfast/Good Friday agreement and the Northern Ireland peace process; a renewal of impetus for the Scottish independence movement; and general tension around the relationship between the devolved and UK tiers of governance. Taken in combination, these issues point to a more fundamental and dangerous aspect of Brexit. It could well be that, in leaving the EU, the UK is depriving itself of a force that served to support its continued existence as a viable single state. The following paragraphs consider the possibility that EU membership was a key component in the viability of the UK as a multi-national polity, in ways that were not necessarily immediately apparent, even to those who supported ‘remain’.

Creating a United Kingdom

To understand this perspective on the UK, it is important to rehearse an historic sequence of events. The UK came into being as a state principally as a consequence of three incorporations: the absorption of Wales into England in the sixteenth century; the Union between Scotland and England early in the eighteenth; and the Union between Ireland and Great Britain early in the nineteenth. The precise characteristics of each of these mergers differed. But their combined effect was to create a single state out of four nations (a model that would later inspire proponents of an integrated Europe). There was some allowance for differences between its components – for instance Scotland retained its own legal, educational and local government systems, and Church. But a key feature of the Union as it developed was that it shared a common set of key rules and institutions, determining the nature of its political, legal and economic relationship with the outside world and its internal operation. A central component of this system was that it developed into a single market – an environment in which trade was free from tariffs and in which the potential for the capacity for the engineering of territorially-specific advantages through regulatory divergence was minimised. As Article VI of the 1706 Treaty of Union, between Scotland and England, stipulated:

‘all parts of the United Kingdom for ever from and after the Union shall have the same Allowances Encouragements and Drawbacks and be under the same prohibitions restrictions and regulations of Trade and liable to the same Customs and Duties on Import and Export And that the Allowances Encouragements and Drawbacks prohibitions restrictions and regulations of Trade and the Customs and Duties on Import and Export settled in England when the Union commences shall from and after the Union take place throughout the whole United Kingdom’.

Joining the EC

Principles of this type would later become central to the EU, with the encouragement of – among others – the Conservative government of Margaret Thatcher. The financial and economic polity envisaged in this passage would become central to the cohesion of the UK. After the UK joined the European Communities in 1973, it came to be encompassed within a larger single market, the existence of which could distract from the earlier importance of this trading aspect of the Union. Leaving the EU has restored the importance of having UK-specific arrangements to guarantee the British internal market. Yet – as we will see – by the time of Brexit, the UK had introduced internal constitutional arrangements that were not easy to reconcile with the maintenance of this British internal market.

England’s role

As the passage quoted above demonstrates, England was the most powerful force within this state – in this instance, providing the regulatory template that others were required to follow. In doing so, its interests were not just economic. England drove the formation of the Union partly out of concern that Scotland and then Ireland might otherwise provide a base for military invasion from the continental mainland. It therefore understandably preferred the model of full incorporation of Scotland and Ireland into the United Kingdom, to a looser arrangement such as that favoured by the Scottish negotiators in 1706, who opened proceedings by requesting what they termed ‘federal union’, within which the Scottish and English legislatures would continue to exist. England secured the more centralised outcome it wanted.

England, then, was the preeminent force in the process of Union-building and in the state that emerged from it. The general imbalance in this arrangement has been a source of discomfort in other parts of the Union. Wales, Scotland and Ireland have each been the site for campaigns either for a more decentralised form of government giving them more control over their own affairs (originally known as ‘home rule’), or outright departure from the Union. Disagreement over the Union has been a source of violent conflict in Ireland, then Northern Ireland. In Wales and Scotland, nationalism has become a political force, most recently from the 1960s onwards, and the independence cause has gained particular ground in Scotland during the twenty-first century. In both Wales and Scotland, a powerful traditional argument in favour of the Union was that it provided access to opportunities in the outside world. The collapse of the Empire called into question this perceived benefit. Participation in European integration from 1973 should be seen partly as a UK response to its loss of imperial power. Though the Scottish National Party was initially sceptical regarding European integration, it has become a firm supporter of this project. Brexit has certainly provided renewed impetus to the independence movement, at least partly through making participation in the UK appear for the Scots and the Welsh less of a route to engagement with the outside world.

Federalism or devolution?

One response to territorial pressures on the Union over time might have been to establish a robust federal system (a relatively vague version of which – as we have seen – was rejected by England in 1706). Such an arrangement would have seen the introduction of a new layer of territorial ‘state’ level governance, with a defined division of responsibilities between it and the existing full UK tier. The UK has never sought to pursue such an option and it may well now be too late for it to do so. Obstacles to such a project seem to have included uncertainties about how to accommodate England within it. There was also cultural resistance from the political centre to the sharing of power, with an attachment to the doctrine of the ‘sovereignty’ of the UK Parliament.

Instead of federalism, the UK response to the centripetal national forces was eventually to adopt the system of asymmetrical devolution that exists today. Most notably, Wales, Scotland and Northern Ireland each has its own directly elected legislature and executive. No such equivalent exists for England, though there have been some limited downward transfers of power to territories within it. Rather than devise a comprehensive system, then, the UK opted for a piecemeal approach. It did not introduce, along with devolution, a new system to ensure that new law-making powers at sub-UK level did not compromise the single market that was a key component of the Union. It is important to note that the arrangements in place now date in the origins to the late 1990s, by which time the single market of the UK – which had joined the European Communities (later the EU) a quarter of a century previously – had been fully absorbed into that of the EU. To preserve its coherence as a single market, the UK therefore relied upon European law: measures to which all EU member states are subject, designed to create and sustain a single European market, in the same way that legal measures creating the UK set out to do. All the devolved systems were made subject to European law. By complying with the rules of the European single market, by extension, they upheld the UK single market.

The Internal Market Bill

Departure from the EU has removed this safeguard for the UK. For the UK to continue to function as a viable state after Brexit, it needs to develop means of protecting the integrity of its single market from within. Efforts to fulfil this objective have already proved controversial and can be expected to continue to do so. A single market necessitates the existence of a uniform corpus of regulations applied consistently throughout the territories included within it. The same politicians who attained power through objecting to this principle when applied at European level now face the challenge of seeking to assert it within the UK. To some extent, it requires decision-making authorities to be vested at full UK level. For instance, agricultural regulations are devolved. The UK government might – as a consequence of a trade agreement it reaches with another trading bloc – wish to alter the rules in this area to allow for the import of products that were, under previous rules derived from EU membership, prohibited. Implementation of this objective might require it to override devolved institutions. The purpose of the Internal Market Bill is to provide it with the powers to do so. The recent express disavowal of this proposed law by the Scottish Parliament (at the request of the Scottish Government) demonstrates the controversy that such a proposition entails (this same Bill, as it applies to Northern Ireland, threatens a violation of international law, and to compromise the peace process). From the devolved perspective, rather than a dispersal of power, Brexit could appear to entail centralisation. In the pre-Brexit era, for advocates of departure, the perceived imposition of rules from the EU was unacceptable. In a post-Brexit era, for many, that decisions should be made at UK level will be similarly objectionable.

Challenges to the continued existence of the UK are likely to become more acute. The independence cause in Scotland, for instance, benefits from a sentiment that an English-dominated set of institutions are interfering in its business. In Northern Ireland the position is more complicated still. The UK and the Republic of Ireland joined the European Communities at the same time. Never before, therefore, has one country been inside the organisation while the other is outside. If the UK is to diverge from the EU in terms of tariff arrangements and market regulations, then difficult questions arise regarding the land border between it and the EU, which runs across the island of Ireland. In an ironic inversion of history, the EU is determined that the island of Ireland should not provide the UK with a back-door into the Customs Union and Single Market. The difficulties the UK has experienced in agreeing internally to and then abiding by a deal with the EU over future arrangements for Northern Ireland arise from this basic problem. If Northern Ireland is forced to distance itself from the Republic and EU as a whole as a consequence of Brexit, the peace process – for which continued EU membership for the whole island of Ireland was an underpinning assumption – will be called into question. If Northern Ireland retains congruity with EU regulations, then it becomes more remote from the remainder of the UK. Each scenario suggests instability – either derived from potential conflict, or structural incoherence – for the UK.

Brexit removes the glue that holds the Union together

It could transpire, then, that participation in the EU was central to the sustenance of the UK. A full appreciation of this point might only be acquired by a practical demonstration of the impact of Brexit upon the cohesion of the Union – by which time the damage will have been done, or at least be in motion. Brexit could amount to a removal of the connective tissue of the UK. Such organic analogies might once have had greater resonance within the Conservative Party than they do today. For the present government, the pursuit and even augmentation of division appears to be a deliberate political tactic. Such an approach appears to threaten the future of the multi-nation Union state. However, present difficulties are not attributable solely to a particular style taken in the pursuit of Brexit. Under any circumstance, reconciling withdrawal from the EU with preservation of the Union would present a serious challenge. The UK has a pervasive domestic narrative of its being an unusually stable polity, untroubled by lack of underlying constitutional consensus and lacking a disposition towards conflict. This interpretation is at the least in need of careful qualification. It has always been disposed towards fundamental internal differences with a territorial aspect. The EU helped ameliorate them. Finding alternative means of binding the state together, if this goal is achievable at all, will not be an easy task.