Authored By: Anshita Nanda
QMUL
Introduction
Brexit is arguably one of the most significant constitutional changes in the modern history of the United Kingdom. Following the UK referendum in 2016, in which a majority of the population voted in favor of leaving the European Union, the UK embarked on a process that culminated in its formal withdrawal from the EU in 2020. The dominant rhetoric of those who campaigned for Brexit rested on the restoration of parliamentary sovereignty, which is often described in constitutional discourse as the reclaiming of legislative autonomy from the shackles of European Union laws. However, such a statement of constitutional reality deserves a closer legal analysis. This article submits that Brexit has not resulted in the absolute restoration of sovereignty but rather revealed the complex nature of sovereignty in the UK’s constitutional reality.
Legal Framework and the Role of the Judiciary
In the process of withdrawal from the European Union, it is important to note that the process was not only political in nature but also very much legal. It is important to note that the UK constitution is uncodified, yet it is subject to certain limitations with regard to the exercise of executive powers, especially when constitutional principles are at stake. This is evident in the Miller case, where the Supreme Court held that the government could not trigger Article 50 of the Treaty on European Union using prerogative powers. Instead, it had to be sanctioned by the Parliament because it would affect the domestic law.
This decision by the Supreme Court not only reinforced the concept of parliamentary sovereignty but also underscored the importance of the rule of law.
The judiciary has again played a vital role in the prorogation crisis, in which the Supreme Court held that the advice of the Prime Minister for prorogation of Parliament was unlawful. Such cases reveal that the role of the judiciary has not been undermined in the context of Brexit, rather it has been emphasized.
From a general perspective, it can be said that these cases reveal that sovereignty in the UK is not vested in Parliament alone, rather it is vested in a system of checks and balances. Brexit has further strengthened the principle that legal accountability is at the heart of the UK’s constitution.
Critical Perspectives on Sovereignty
The assertion that Brexit resulted in a restoration of sovereignty is based on the assumption that the UK’s membership of the EU resulted in a loss of parliamentary sovereignty due to the doctrine of the supremacy of EU law. This meant that any legislation inconsistent with EU law could be disapplied by national courts. The Brexit decision resulted in the termination of EU law supremacy over national law, thereby allowing Parliament to legislate without being answerable to EU law.
However, this assertion of sovereignty is also open to considerable criticism. Firstly, the assertion of absolute sovereignty is not tenable in a globalised world. The UK is also answerable to a number of international obligations and is not free to act independently.
Secondly, the Brexit process has highlighted the internal constitutional complexities within the UK. Indeed, the repatriation of powers from the EU to the UK posed complex constitutional issues in terms of the distribution of powers between Westminster and the devolved administrations. Scotland and Northern Ireland, in particular, have expressed their constitutional concerns about the centralization of powers in Westminster, which challenges the idea of the single sovereign entity. Moreover, the Northern Ireland Protocol controversy is evidence of the new legal constraints imposed by the Brexit process.
In academic circles, the constitutional significance of the Brexit process is subject to debate. Indeed, some writers argue that the Brexit process is no more than a symbolic exercise in the assertion of parliamentary sovereignty. Others argue that the Brexit process highlights the fragmented nature of sovereignty, which is no longer the absolute concept developed by Dicey.
Comparative and International Perspectives
A further comparison serves to reinforce the limitation of the sovereignty argument. Within the context of the European Union, there has been a pooling of sovereignty among the different countries. Essentially, this does not necessarily mean that there is no longer any sovereignty, merely that it has been redefined in terms of cooperation.
The context of Brexit has been one of a desire for national sovereignty. Nevertheless, outside of the context of the EU, there remains a need for the UK to function within a framework of international legal agreements. For example, trade agreements often necessitate a level of conformity in terms of regulatory standards. Similarly, international human rights agreements have already begun to influence domestic legal standards.
Moreover, comparative constitutional practice shows that other countries have succeeded in asserting constitutional limitations on supranational authority without withdrawing from the EU. This implies that the loss of sovereignty due to EU membership may not have been so significant after all. Instead, it may be argued that Brexit is a political decision based on concerns about sovereignty rather than a legal imperative.
Furthermore, the continuation of the influence of international law shows that the reality of sovereignty is not so clear-cut. Countries do not act in isolation but are part of a complex network of obligations and dependencies. Therefore, sovereignty is not an absolute reality but a relative one.
Conclusion
Brexit was sold as a solution to restore parliamentary sovereignty and regain power over domestic law-making. Nevertheless, an evaluation of its legal implications presents a more complex scenario. Although the UK has managed to regain legislative autonomy from the EU, various limitations exist.
The intervention of judges in the Brexit procedure has also reaffirmed the need to respect constitutional rules such as the rule of law and separation of powers. Nevertheless, various international and constitutional limitations indicate that sovereignty is not absolute.
In conclusion, Brexit has marked not a revival of traditional sovereignty but a transformation of sovereignty in a complex legal system. The idea of sovereignty appears to be more symbolic than real, merely an aspiration and not a legal reality. Therefore, Brexit has marked a constitutional evolution, particularly in terms of sovereignty in a global world where sovereignty is a continuous negotiation.
OSCOLA Reference List
Cases
R (Miller) v Secretary of State for Exiting the European Union [2017] UKSC 5
R (Miller) v Prime Minister [2019] UKSC 41
Costa v ENEL (Case 6/64) [1964] ECR 585
Legislation
European Union (Withdrawal) Act 2018
Human Rights Act 1998
Books and Journal Articles
Mark Elliott and Robert Thomas, Public Law (3rd edn, OUP 2017)
Paul Craig, ‘Brexit: A Drama in Six Acts’ (2016) 41 European Law Review 447
Mark Elliott, ‘The Supreme Court’s Judgment in Miller: In Search of Constitutional Principle’ (2017) 76 Cambridge Law Journal 257
Online Sources
Nick Barber, Jeff King and Alison L Young, ‘Prerogative and the Third Source’ (UK Constitutional Law Blog, 2017) <https://ukconstitutionallaw.org> accessed 31 March 2026
International Materials
Treaty on European Union (consolidated version)
European Convention on Human Rights 1950
