Most countries have their basic principles embodied in a single written document, called ‘constitution’. British constitution is unusual because it doesn’t have the form of a single written document and therefore it places supremacy on statutes, and not on the constitutional text itself. The concept of British constitution was defined as ‘a body of rules, conventions and practices which describe, regulate or qualify the organisation, powers and operation of government and the relations between persons and the public authorities’ ¹ . The three main sources where British constitution draws its principles from are: constitutional statutes, case law and constitutional conventions. One such principle is the parliamentary sovereignty. Having set out a brief background of the UK constitution, we will discuss this concept and its effects.
The start point in this issue is Dicey’s doctrine, which sets the concept of ‘parliamentary sovereignty’ at the basis of constitutional law. He defines the concept as meaning ‘that Parliament… has, under the English constitution, the right to make or unmake any law whatever; and, further, 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’ ² . The doctrine establishes the legal supremacy of statute, which means that Parliament is the highest authority in the state and that courts are under an obligation to apply Acts of Parliament without questioning their validity. There are both positive and negative effects of this principle.
One positive effect is that Parliament can legislate on any matter. An example of Parliament legislating inconsistently with international law is provided by Cheney v Conn ³ case, where a taxpayer appealed against an assessment of income tax, claiming that the decision had the illegal purpose of building nuclear weapons, which was against international law. His appeal failed. This power is also illustrated by Mortensen v Peters⁴. In this case, Mortensen was charged for illegally fishing within a five mile limit, while the limit was claimed to be of three miles under international law. He claimed that the statute establishing the three miles limit should exclude foreigners, but his defence failed.
Another positive effect of the doctrine is that Parliament cannot bind itself or its successors. Every Parliament is supreme, therefore a Parliament cannot bind future Parliaments. The application of this rule is ensured by the doctrine of implied repeal which states that if two Acts of Parliament conflict, the latter Act is enforced, while the first one is automatically invalidated. This principle was applied in Ellen Street Estates Ltd v Minister of Health ⁵ . This case concerned the application of the Acquisition of Land Act 1919, which assessed the compensation given to landowners for the compulsory acquisition of land for public purposes. Although the Act was supposed to apply only to past enactments, it was argued that it also applied to later Acts. The CA held that the Act cannot bind future Parliaments.
There are also negative aspects of the doctrine of parliamentary sovereignty. One such effect is that nobody can set aside an Act of Parliament. After the Bill of Rights 1688 was introduced, it was widely accepted that an Act of Parliament is the supreme power in the state. Therefore courts could no longer declare an Act of Parliament invalid. The enrolled act rule provides that once an Act of Parliament is passed, it becomes law. This means that it is the Parliament’s responsibility to decide the procedures to be followed in order to pass an Act, and once an Act is passed, courts have no power to question the legality of the followed procedures. This view was adopted in Edinburgh and Dalkeith Railway Co v Wauchope ⁶ , where it was held that an Act of Parliament was invalid because it had failed to notice the persons to whom the Act referred to, according to the parliamentary standing orders. The argument was subsequently dropped. The same issue arose in Lee v Bude and Torrington Junction Rly Co ⁷ , where an Act of Parliament was challenged again, this time ‘on the ground that the promoters of the Act had fraudulently misled Parliament as to the facts and the promoters’ true purposes’ ⁸ , but the argument failed in this case as well. Another similar case is Pickin v British Railways Board ⁹, where the claimant questioned the rightness of the process followed in Parliament to pass the British Railways Act. The CA held that this was a valid claim, but the HOL disapproved this decision.
Therefore, the concept of parliamentary sovereignty is the basic principle of the UK constitution. There have been a number of challenges to this principle, which leads us to question whether Parliament is still sovereign nowadays. The more important challenges are: manner and form limitations, territorial limitations and scope and subject limitations.
An example of limitation as to manner and form is illustrated in Jackson v Attorney General ¹⁰. The normal procedure for a Bill to become an Act of Parliament is that it has to pass through three readings in each House and then receive Royal Assent. The Parliament Act 1911 gave the HOC limited power to legislate without the HOL. The HOL’s power to delay bills was reduced from two years to only one. The present case challenged the validity of the Hunting Act 2004 and the Parliament Act 1949, but the HOL held that the two acts were valid.
Territorial limitations refer to the Parliament’s power to legislate outside its geographical limits, in the way that any law passed by a Parliament outside these limits will be ineffective. This view was adopted by the courts in two relevant cases: Blackburn v Attorney-General ¹¹ and Manuel and Others v Attorney-General ¹². According to Lord Denning in Blackburn ¹¹, the concept of parliamentary sovereignty can sometimes be limited by ‘practical politics’. This idea was supported by Megarry VC in Manuel v AG ¹² , who said that ‘legal validity is one thing, enforceability is another’.
Another type of limitation refers to scope and subject. In Thoburn v Sunderland City Council ¹³, Laws LJ created a hierarchy of statutes, which divides them into ‘ordinary’ and ‘constitutional’ statutes. There are three constitutional statutes which have had a more important impact on parliamentary sovereignty: the European Communities Act 1972, the Human Rights Act 1998 and the Devolution Acts. The ECA 1972 required legislation to be interpreted compatibly with European law, which has limited the concept of parliamentary sovereignty. The HRA 1998 brought the Convention rights into domestic law, which is an additional limitation on Parliament. The UK Parliament has transferred some of its power to devolved territories through devolution acts thus UK still has the power to legislate on devolved territories, but it can only do so with the devolved Parliaments’ consent.
Although the concept of parliamentary sovereignty has represented the core principle of the UK constitution for a long time, nowadays it is subject to a large number of challenges, therefore Parliament can no longer be regarded as the supreme power in the state.
Bibliography:
Allan, ‘Parliamentary Sovereignty: Law, Politics and Revolution’ (1997) 113 L.Q.R. 443.
Bradley, ‘The Sovereignty of Parliament- Form or Substance?’ in Jowell & Oliver, The Changing Constitution (6th edn)
Lectures and supervisions handouts
Sellick, J with Reynolds, J Constitutional and Administrative Law (Hodder Education, 2009)
Turpin, C and Tomkins, A British Government and the Constitution (The Law in Context Series, CUP, Cambridge 2009)
Wade, ‘Sovereignty- Revolution or Evolution?'(1996) 112 L.Q.R. 568.
Updated 15 March 2026
This article was written when the United Kingdom remained subject to EU law under the European Communities Act 1972. That position has since changed fundamentally. The UK left the European Union, and the European Communities Act 1972 was repealed by the European Union (Withdrawal) Act 2018. EU law no longer has supremacy over Acts of Parliament in domestic law, and the ECA 1972 can no longer be treated as a constitutional statute in the sense described in Thoburn v Sunderland City Council [2002] EWHC 195. The cases discussed in the article on EU membership as a limitation on parliamentary sovereignty (including the Thoburn hierarchy insofar as it applied to the ECA 1972) require significant qualification in light of Brexit.
The Human Rights Act 1998 remains in force. The article’s description of it as a limitation on Parliament should be read carefully: the HRA 1998 does not permit courts to strike down primary legislation; section 4 declarations of incompatibility leave parliamentary sovereignty formally intact, which the article does not fully explain. The Government announced plans to replace the HRA 1998 with a Bill of Rights, but as of the date of this note that proposal has been shelved and the HRA 1998 remains in force.
The devolution settlement has continued to evolve. The Scotland Act 2016, Wales Act 2017, and ongoing developments in Northern Ireland have expanded devolved competences. The Sewel Convention, whereby Westminster does not normally legislate on devolved matters without consent, was placed on a statutory footing by the Scotland Act 2016, though courts have confirmed it remains a political convention and is not legally enforceable: R (Miller) v Secretary of State for Exiting the European Union [2017] UKSC 5.
The core principles described in the article — Dicey’s doctrine, the enrolled bill rule, implied repeal, and the cases discussed — remain broadly accurate as statements of constitutional law. However, given the significance of Brexit, students should treat the section on the ECA 1972 as substantially outdated and consult current materials on post-Brexit constitutional arrangements.
