Authored By: Hanene Latrache
Hanene Latrache
Abstract:
The UK has an uncodified constitution founded on the doctrine of Parliamentary Sovereignty, which means that Parliament can make or unmake any law, and Acts of Parliament cannot be questioned by the courts. However, since the end of the 20th century, a plethora of legal, political, and international factors have added complexity to the practicality of Parliamentary Sovereignty operating. This article analyses the current scope of Parliamentary Sovereignty in the United Kingdom, particularly highlighting judicial developments (such as Thoburn, Jackson, Factortame, and both Miller judgements), statutory modifications (such as the European Communities Act 1972 and the Human Rights Act 1988), as well as the application of Parliamentary sovereignty in Crown dependencies and territories overseas. It will also argue that Parliamentary sovereignty has remained intact, at least formally, and is not abolished, however, this formal continuity increasingly diverges from constitutional practice as it is weakened by international obligations, devolution, and the rise of the influence of rights and UK courts. The article will conclude with some suggestions for change in regards to parliamentary practice and the preservation of legitimacy, while keeping to the constraints imposed by the rule of law.
Introduction: Dicey’s Classic Formulation and Contemporary Pressure
A.V. Dicey’s statement that “Parliament has the right to make or unmake any law whatever,” and that “no person or body is recognised by the law of England as having a right to override or set aside the legislation of Parliament”, puts into simple terms the longstanding historical and political functioning and practices of UK constitutionalism1. Such wording provided a clear image of the hierarchical structure of its constitution, with Parliamentary Acts standing at the very top, not subject to questioning from any other body or person.
This view reflects a formalist approach. Formalism insists that sovereignty is a legal fact, not influenced by politics or morals, holding a strict believe that Parliamentary sovereignty is absolute and unaffected by political pressure, conventions, or judicial involvement. If adopted in practice, this vire means courts must apply Acts of Parliament as valid laws and trace any limiations to Parliament’s will.
Though formalism provides clarity and certainty in regards to legal authority, it can be widely contested when compared with modern constitutional developments. In recent years this supremacy has been weakened and less sovereign, particularly due to the UK’s membership of the European Union and Community law taking effect on the UK legal system. The supremacy is undermined further by other factors, such as the Human Rights Act 1988, devolution of power, and a growth in judicial review and constitutional reasoning’s influence on the politics of Parliament and its operations in practice. This article analyses these shifts by assessing to what extent formalist accounts continue to give accurate explanations of Parliamentary sovereignty, and where they fail to do so in line with the constitutional reality of the UK.
The core of the Law: Statute, Common Law, and the Courts
The formal position of Parliament and law-making
The formal position of the UK Parliament is that it is sovereign and remains supreme. The European Communities Act 1972, as well as the Human Rights Act 1998 and any other statutes were legislated by Parliament, and according to the doctrine of Parliamentary Sovereignty, these legislations could legally be repealed by Parliament at any time. There is no law that presently prevents Parliament from doing so, and Parliament cannot bind itself2. This understanding reflects the rule of recognition, coined by H.L.A Hart, which explains that because the courts treat Acts of Parliament as sovereign, that is what makes them sovereign and therefore legitimises them within the law3. Though Hart is not a formalist, formalists do lean heavily on Hart’s rule of recognition to reflect the persistence of formalism in the law as well as to enforce Parliamentary sovereignty by the courts despite limitations.
This can be put into perspective if considering that, in theory, Parliament could legislate that “smoking in the streets of Paris is an offence”, and it would indeed be an offence. However it would not take effect in France as the courts of France would not recognise this law as binding over them. This demonstrates the truth in formalist claims that sovereignty operates within the legal system as long as the courts recognise it, but also shows limits of sovereignty outside of its jurisdiction’s scope4.
EU Primacy and Factortame
While the UK was a part of the European Union, the courts had accepted EU law taking effect domestically through section 2(1) of the European Communities Act 1972. In R (Factortame Ltd) v Secretary of State for Transport (No 2), the House of Lords approved temporary protection against a Parliamentary piece of legislation to protect Community law imposed by the EU, which is a decision that highlighted the limits on Parliament’s freedom as long as it applied EU law domestically5. Factortame is cited frequently as the point in time where the formalist idea of Parliament’s unlimited power had to face the practical constraints that come with international commitments.
Factortame can show some weaknesses in formalism, as the courts were not undermining Parliamentary sovereignty but highlighting its ability to essentially bind itself once it agrees to give some sovereignty to foreign agreements like the European Communities Act 1972, which is a moment where unlimited Parliamentary power encountered practical restraint. However, the formalist approach was not abandoned, as it is explained that Parliament had chosen to apply EU law domestically in 1972 and therefore it was Parliament’s own will to be in this position, explaining the strengths as well as the limitations in formalist approaches and its tendency to focus mainly on legal authority without the context in which it is applied in.
Constitutional Statutes and Thoburn
Judges have also given some statutes a “special” status that protects them from implied repeal, primarily noted in Thoburn v Sunderland City Council, where Laws J held that some statutes with constitutional influences cannot be repealed through implied repeal and must use express and clear wording in order to do so6. This included the European Communities Act 1972, and the Human Rights Act 1998. Although this may seem to qualify Parliamentary sovereignty, it may still be understood in formalist terms as Parliament still being able to repeal constitutional statutes, as long as it does so expressly. The courts are not to override Parliamentary decisions, but to insist upon clarity if Parliament wishes to alter its pre-existing wills. However, it can be argued that this is a shift in power towards the judiciary and is allowing the courts to control conditions of repeals, which creates a limitation in the formalist approach that has yet to be resolved.
Constitutional principles and judicial engagement (Jackson)
Although the traditional belief is that Acts of Parliament cannot be questioned by the courts, and even expressly stated by Dicey above, Jackson v Attorney General qualified this view, as the House of Lords accepted on a majority vote that the courts have the right to question the validity of legislation if fundamental constitutional principles were involved, and highlighted that Acts of Parliament are not above scrutiny if they do not conform to the rule of law. Lords Steyn and Hope’s views in Jackson reflected a willingness to treat the constitution as something that is always speaking, and developing over time, rather than something fixed and unchanged. They believe in allowing the courts a less mechanical role and more of a say on the application of the law.7
However, this does not mean it rejected formalism in its entirety, but instead examined if Parliament validly acted and kept its inquiries based on legislation and statutes instead of undermining its supremacy.
Courts as constitutional referees – Miller I and Miller/Cherry (2017, 2019)
Two recent Supreme Court decisions reframed judicial interaction with Parliament and Government. R (Miller) v Secretary of State for Exiting the European Union (2017) denied the executive the power to trigger Article 50 TEU to withdraw from the EU without Parliamentary authorisation first. They required Parliament to legislate them to change the domestic rights that the statute and convention had protected8. Similarly in R (Miller) v The Prime Minister; Cherry v Advocate General for Scotland (2019), the Supreme Court declared it unlawful for the Prime Minister to prorogue Parliament for extended periods as it frustrated Parliamentary scrutiny and did not conform to constitutional principles, which meant the prorogation order was quashed9.
Such decisions reinforce formalist constitutional principles that the executive respects Parliamentary sovereignty and highlights their collaborative roles, and that the court acted in the interest of Parliament to protect its supremacy, which reinforced the formalist notion that parliament is the central point of constitution in the UK. However, by relying on constitutional principles rather than explicit statutory limits, the judiciary is seen to be departing further from formalist practices even when affirming Parliament’s supremacy.
Parliamentary Sovereignty, Human Rights, and Statutory Dialogue:
Parliament had signed the European Convention on Human Rights in 1951, however it was not fully binding until 1998, when the Human Rights Act 1998 incorporated its rights into domestic laws and eventually took the ECHR from an international treaty to enforceable domestic rights. The Human Rights Act 1998 created a mechanism for courts which allowed them to issue a declaration of incompatibility if an Act did not comply with the ECHR, and although the declaration is not legally binding, it puts political pressure on Parliament to review and reform Acts to ensure compatibility going forward. The HRA does not void primary legislations as Parliament is supreme and retains final say in conformation with Convention rights10, however the HRA also strengthened rights-based reasoning within UK Public law as it improved communication between the courts and Parliament. After all, Parliament is supreme because the courts say it is supreme.
For formalists, this is constitutionally consistent as such duties for the courts exist because Parliament wanted them to exist, and Parliament can decide at any moment to repeal the Acts altogether if it so wishes and cannot be stopped from doing so (in theory).
Devolution, Federal Constraints, and parliamentary Reach
Parliament devolved power to Scotland, Wales, and Northern Ireland, which redistributed law-making abilities throughout the UK. Westminster still has legal power to legislate on their devolved areas, however the constitutional conventions and political realities significantly limit the scope in which Parliament can do so without public scrutiny or political uproar. For example, The Scotland Act 1998 devolved power to Scotland, yet Parliament could still in theory legislate in Scotland if it wished to do so11. But due to the political expectations and conventions, it is highly unlikely and discouraged to do so. Although this may benefit the other countries within the UK and allow them political control over their own lands, it highlights how constitutional checks and conventions restrict Westminster’s practical freedom. Formalists who only look at the word of the law do not consider the effects of such factors in practice as they focus on the doctrine that Parliament is sovereign and can do as it pleases, but when faced with political backlash that is very real and prominent in the 21st century, it is not prepared to give an answer as to the power of Parliament in such cases, and remain stagnant on emphasising that devolved powers are legally subordinate to Westminster legislation.
Crown dependencies and Overseas Territories: Parliament’s reach beyond the British Isles
Parliamentary sovereignty extends beyond the geographical location of the UK. Crown Dependencies (Bailiwicks of Jersey and Guernsey, and the Isle of Man), are not part of the Uk but rather are self-governing possessions of the Crown. They have their own legislation and legal systems. The UK’s practice is that they retain responsibility for good governance and international representation, and do not extend Acts to Dependencies without expressly informing them or gaining consent12. In practice, this follows the formalist approach, that Parliament retains ultimate power, yet shows the consistent restraints within Parliament, as the UK only ever exercised such power in exceptional circumstances, and generally allows them to self govern. However, as this rule goes for all their overseas territories too, it shows
Parliament’s formal power therefore coexists with other territories’ legislative systems, which places heavy practical and constitutional restraints on Parliament, and may juxtapose some of the formalist ideas of supremacy.13
International Law, Treaties, and limits of Domestic Supremacy
Parliament is increasingly constrained through the effects of globalisation and obligations imposed by treaties. While Parliament can legislate in opposition to international treaties in theory, diplomatic, economic, and reputational losses are on the line in doing so, opening Parliament up to international scrutiny and damaging relations. Extensions of treaties to Crown Dependencies and Overseas Territories ordinarily require UK action14. Formalists express a clear line between legal validity and political consequence, recognising potential influence on Parliament internationally, but maintaining that it will not limit Parliament’s own legislative competence on common law. However, as seen in the post-Brexit period, Parliamentary choices, such as how remaining EU law is treated, frequently interact with international commitments, as well as the institutional structure of the UK constitution. In practice such commitments, especially due to their international nature, create fundamental political and normative restraints on Parliament’s legislative supremacy, even without any legal barriers to do so domestically.
Has Parliamentary Sovereignty eroded?
Formally, Parliamentary sovereignty is still being practiced. Parliament is still able to legislate or repeal as it pleases, however the practicality of doing so has changed, as political pressure and international commitments constantly mediate the exercising of this power.
Man (Gov.uk) and Fact sheet on the UK’s relationship with the Crown Dependencies (Feb 2020). https://www.gov.uk/government/publications/crown-dependencies-jersey-guernsey-and-the-isle-of-ma n and Formalism as a perspective is still a good theory to explain legal supremacy, however it fails in other factors such as explaining sovereignty in a modern UK context.
Conclusion: Parliamentary Sovereignty, Formalism, and Democratic Legitimacy
Dicey’s classic statement that Parliament can “make or unmake any law,” and that nobody may override it, remains consistent with the constitutional reality of the UK and its laws. Parliament is still at the top of the legal hierarchy within the jurisdiction and the courts continue to invalidate primary legislations, continuing to uphold its supremacy above all else. In this context, formalist views do hold significant value in explaining the legal authority and hierarchy of the constitution and Parliament. Even the limitations that came from Factortame, the Human Rights Act 1998, and the Miller cases came from Parliament’s own choices or judicial efforts that intended to protect Parliament’s supremacy.
However, formalism’s limits are shown when looking at the formalist view as a whole. Though much of the view survives when looking at the law only, when adding the context of political constraints, devolution, rights, and international commitments, it is clear that they all have an impact on how Parliament acts: not on its own but from influence by other factors. To keep democratic legitimacy, Parliamentary sovereignty must be open to scrutiny and respect the courts and international commitments they are involved with. The UK constitution therefore does not reflect the erosion of sovereignty, but rather reflects the adaptability of centuries old law and doctrines in a contemporary and modern context.
Reference(S):
1 A V Dicey, An Introduction to the Study of the Law of the Constitution (10th edn, Macmillan 1959) ch 3 (classic formulation of parliamentary sovereignty).
2 European Communities Act 1972, c 68. See also R (Factortame Ltd) v Secretary of State for Transport (No 2) [1991] 1 AC 603 (HL).
3 H L A Hart, The Concept of Law (3rd edn, OUP 2012) 94-99
4 John Stanton and Craig Prescott, Public Law (4th edn, OUP 2025)
5 R (Factortame Ltd) v Secretary of State for Transport (No 2) [1991] 1 AC 603 (HL)
6 Thoburn v Sunderland City Council [2002] EWHC 195
7 Jackson v Attorney General [2005] UKHL 56, [2006] 1 AC 262
8 R (Miller) v Secretary of State for Exiting the European Union [2017] UKSC 5, [2018] AC 61
9 R (Miller) v The Prime Minister; Cherry v Advocate General for Scotland [2019] UKSC 41.
10 Human Rights Act 1998, c 42, particularly ss 3–4 (interpretation and declarations of incompatibility). See House of Commons Library explainer: Parliamentary sovereignty and the European Convention on Human Rights (6 November 2014). https://commonslibrary.parliament.uk/parliamentary-sovereignty-and-the-european-convention-on-hu man-rights/ accessed 13 December 2025.
11 Scotland Act 1998
12 UK Government guidance and factsheets on Crown Dependencies and Overseas Territories explain the special constitutional arrangements and the limited circumstances in which UK Acts are extended: Ministry of Justice/Government guidance, Crown Dependencies: Jersey, Guernsey and the Isle of https://assets.publishing.service.gov.uk/media/5e398990e5274a08e229ca0f/crown-dependencies-fact sheet-february-2020.pdf accessed 13 December 2025. See also House of Commons Library, The Crown Dependencies (CBP-8611, 12 Sept 2025). https://researchbriefings.files.parliament.uk/documents/CBP-8611/CBP-8611.pdf accessed 13 December 2025.
13 For the constitutional status of Overseas Territories see The Overseas Territories and the Home Office and various Commons Library briefings; see also the constitutions of individual territories (Orders in Council) as published on legislation.gov.uk or gov.uk guidance on treaties and territories. e.g. Overseas Territories and the Home Office (Home Office, April 2012) https://assets.publishing.service.gov.uk/media/5a74db66ed915d3c7d5287cf/overseas-territories.pdf accessed 13 December 2025;
14 Treaties and extension to Territories/Crown Dependencies: UK Government guidance, UK Treaties: extension of treaty obligations to Crown Dependencies and Overseas Territories. https://www.gov.uk/guidance/uk-treaties accessed 13 December 2025.
