Introduction
The concept of parliamentary sovereignty is a cornerstone of the United Kingdom’s constitutional framework, establishing Parliament as the ultimate source of legal authority. This principle, often described as the bedrock of British public law, asserts that Parliament has the power to make or unmake any law, and no other body can override its legislation. However, in an era of evolving political, legal, and social landscapes, this traditional view of parliamentary supremacy faces significant challenges, including the influence of European Union (EU) law (prior to and post-Brexit), the role of devolution, and the judiciary’s growing assertiveness. This essay aims to explore the foundations of Parliament’s legal authority, critically assess its position as the ultimate source of power, and evaluate key challenges to this authority. By examining historical doctrines, landmark cases, and contemporary developments, the discussion will highlight both the enduring significance of parliamentary sovereignty and the complexities that threaten to undermine it.
The Doctrine of Parliamentary Sovereignty
Parliamentary sovereignty is a fundamental principle of the UK’s uncodified constitution, often attributed to the legal theorist A.V. Dicey. Dicey (1885) articulated this doctrine as comprising three core elements: Parliament can make or repeal any law; no Parliament can bind a future Parliament; and no court or body can challenge the validity of an Act of Parliament. This establishes Parliament—comprising the House of Commons, House of Lords, and the Monarch—as the supreme law-making authority in the UK. Historically, this principle emerged from the aftermath of the Glorious Revolution of 1688-89, which cemented parliamentary dominance over the monarchy through the Bill of Rights 1689, reinforcing the idea that legislative power rests solely with elected representatives (Bradley and Ewing, 2011).
The practical implications of this doctrine are evident in Parliament’s ability to enact legislation on any matter, ranging from constitutional reforms to mundane regulations, without legal restraint. For instance, Parliament’s capacity to abolish itself, as seen in the passage of the Parliament Acts 1911 and 1949, which reduced the House of Lords’ veto power, demonstrates its unfettered authority. Furthermore, the judiciary consistently upholds this principle by refusing to question the content or validity of statutes, as affirmed in cases like Pickin v British Railways Board (1974), where the House of Lords reiterated that courts cannot invalidate parliamentary legislation (Loveland, 2018). This entrenched position, therefore, appears to confirm Parliament’s status as the ultimate legal authority. However, while the theoretical framework remains robust, practical and political realities introduce significant challenges to this supremacy.
Challenges from European Union Law
One of the most prominent challenges to parliamentary sovereignty during the latter half of the 20th century was the UK’s membership in the European Union. Upon joining the European Economic Community in 1973 through the European Communities Act 1972, the UK accepted the supremacy of EU law over domestic legislation in areas of shared competence. This was explicitly demonstrated in the landmark case of R v Secretary of State for Transport, ex parte Factortame Ltd (No 2) (1991), where the European Court of Justice ruled that UK courts must disapply domestic legislation that conflicted with EU law, a ruling upheld by the House of Lords (Craig, 2017). This effectively undermined the traditional notion that no body could override parliamentary statutes, as EU law temporarily took precedence.
Even after the UK’s withdrawal from the EU in 2020, the legacy of EU law continues to pose challenges. The European Union (Withdrawal) Act 2018 retains elements of EU-derived legislation as “retained EU law,” which complicates the full restoration of parliamentary sovereignty. While Parliament regained the ability to repeal or amend these laws, the sheer volume of legislation and the practical necessity of maintaining legal continuity highlight the enduring influence of external legal frameworks. Thus, while Brexit has arguably reasserted parliamentary authority in theory, the practical entanglements of EU law remain a lingering constraint.
The Impact of Devolution
Another significant challenge to Parliament’s ultimate authority arises from the devolution of powers to Scotland, Wales, and Northern Ireland, initiated through statutes such as the Scotland Act 1998 and the Government of Wales Act 1998. Devolution grants these regions legislative competence over specific areas, such as education and health, creating a quasi-federal structure within a traditionally unitary state. While Parliament retains the legal power to repeal devolution statutes—upholding the principle that it cannot be bound by previous legislation—political realities render such actions highly impractical due to potential backlash and constitutional crises (Bogdanor, 2009).
Moreover, devolution raises questions about the uniformity of law across the UK. For instance, the Scottish Parliament’s ability to legislate on criminal justice results in divergent legal frameworks, challenging the notion of a singular parliamentary authority. The Supreme Court’s role in resolving disputes over devolved powers, as seen in Miller v Secretary of State for Exiting the European Union (2017), further complicates matters by introducing judicial oversight into what was once considered a purely political domain (Elliott and Thomas, 2017). Therefore, while devolution does not legally undermine parliamentary sovereignty, it creates practical and political constraints that dilute its absolute nature.
Judicial Assertiveness and Human Rights Law
The judiciary has increasingly posed a challenge to parliamentary sovereignty through the incorporation of human rights law and a more assertive interpretive role. The Human Rights Act 1998 (HRA) allows courts to issue declarations of incompatibility when domestic legislation conflicts with the European Convention on Human Rights, although such declarations do not invalidate statutes. Cases like A v Secretary of State for the Home Department (2004), concerning the detention of suspected terrorists, illustrate how judicial rulings can pressure Parliament to amend legislation, even if formal sovereignty remains intact (Kavanagh, 2015).
Additionally, judicial review has expanded in scope, with courts scrutinising the exercise of executive powers derived from statutes. The landmark R (Miller) v Prime Minister (2019) decision, which declared the prorogation of Parliament unlawful, demonstrated the judiciary’s willingness to intervene in matters of parliamentary procedure, indirectly challenging the notion of unchecked legislative authority (Elliott, 2020). Critics argue that such developments represent a shift towards a more balanced constitution, where parliamentary sovereignty is tempered by judicial oversight. However, supporters of traditional doctrine maintain that, as courts cannot strike down statutes, Parliament remains ultimately supreme.
Conclusion
In conclusion, the UK Parliament stands as the ultimate source of legal authority, underpinned by the doctrine of parliamentary sovereignty as articulated by Dicey and reinforced through historical and judicial precedents. Its ability to enact or repeal any law without legal constraint remains a defining feature of the British constitution. Nevertheless, this authority faces substantial challenges from the lingering impact of EU law, the practical implications of devolution, and the judiciary’s growing role in scrutinising legislative and executive actions. While none of these challenges legally displace parliamentary sovereignty—since Parliament retains the power to repeal or amend any conflicting framework—they introduce significant political and practical constraints that question its absolute nature. Indeed, the evolving constitutional landscape suggests a move towards a more balanced distribution of power, where parliamentary authority, though theoretically supreme, must navigate complex modern realities. This tension between theory and practice remains a critical area of debate in UK public law, with implications for future constitutional reforms and the preservation of democratic accountability.
References
- Bogdanor, V. (2009) The New British Constitution. Hart Publishing.
- Bradley, A.W. and Ewing, K.D. (2011) Constitutional and Administrative Law. 15th edn. Pearson Education.
- Craig, P. (2017) EU Law: Text, Cases, and Materials. 6th edn. Oxford University Press.
- Dicey, A.V. (1885) Introduction to the Study of the Law of the Constitution. Macmillan.
- Elliott, M. (2020) ‘The Supreme Court and the Constitution after Miller (No 2)’, Public Law, pp. 48-65.
- Elliott, M. and Thomas, R. (2017) Public Law. 3rd edn. Oxford University Press.
- Kavanagh, A. (2015) Constitutional Review under the UK Human Rights Act. Cambridge University Press.
- Loveland, I. (2018) Constitutional Law, Administrative Law, and Human Rights: A Critical Introduction. 8th edn. Oxford University Press.
