# Critically consider the position of Parliamentary sovereignty in light of the United Kingdom’s membership in the European Union.
## Introduction
The doctrine of Parliamentary sovereignty is a fundamental principle of the United Kingdom’s constitution. Traditionally defined by A.V. Dicey, it asserts that Parliament has the power to make or unmake any law, that no Parliament can bind its successors, and that no body can question the validity of an Act of Parliament (Dicey, 1915). The UK’s membership in the European Union (EU) from 1973 to 2020 presented a significant and direct challenge to this doctrine. This essay will argue that while EU membership necessitated a practical limitation on the exercise of Parliamentary sovereignty through the acceptance of EU law supremacy, ultimate or ‘legal’ sovereignty was retained by Parliament, as demonstrated by the fact that membership was a voluntary arrangement that could be, and was, undone.
## The European Communities Act 1972 and the Supremacy of EU Law
The mechanism for the UK’s acceptance of EU law was the European Communities Act 1972 (ECA 1972). This short but constitutionally powerful statute acted as a ‘conduit pipe’ through which EU law flowed into the UK legal system. Section 2(1) of the Act gave direct effect to enforceable EU law without the need for further legislation. Crucially, section 2(4) required that any UK legislation, whether passed before or after the 1972 Act, be construed and have effect subject to EU law.
This created a direct conflict with Parliamentary sovereignty. The European Court of Justice (ECJ) had established the supremacy of EU law in cases such as *Costa v ENEL* (Case 6/64) [1964], stating that the law stemming from the Treaty could not be overridden by domestic legal provisions. By enacting the ECA 1972, it appeared Parliament had accepted that a separate legal order, with its own rule of supremacy, would take priority over domestic Acts, challenging the core Diceyan idea that no one could override an Act of Parliament.
## The Disapplication of an Act of Parliament in *Factortame*
The tension between Parliamentary sovereignty and EU law supremacy came to a head in the landmark case of *R v Secretary of State for Transport, ex p Factortame Ltd (No 2)* [1991] 1 AC 603. The case concerned the Merchant Shipping Act 1988, which was passed by the UK Parliament to restrict access to UK fishing quotas. Spanish fishing vessel owners argued that the Act discriminated on grounds of nationality, contrary to EU law. The House of Lords, following a ruling from the ECJ, granted an injunction to ‘disapply’ the relevant sections of the Merchant Shipping Act 1988 because they conflicted with EU law.
This decision was unprecedented. For the first time, a UK court had suspended the effect of an Act of Parliament. This appeared to be a clear a rejection of the traditional view of sovereignty; the judiciary was effectively declaring that an Act of Parliament was not to be applied, directly contradicting the principle that no body can question the validity or effect of a statute. From this perspective, EU membership fundamentally altered and diminished Parliamentary sovereignty.
## A Voluntary and Reversible Limitation
However, the courts justified their decision in *Factortame* not as an abandonment of sovereignty, but as an application of it. Lord Bridge argued that in passing the ECA 1972, Parliament had voluntarily accepted the limitation of its powers for as long as the UK remained a member of the EU. The courts, in giving priority to EU law, were not acting against Parliament’s will but were simply following the instructions given to them by Parliament in section 2(4) of the 1972 Act.
This perspective suggests that sovereignty was not lost, but was merely qualified by Parliament’s own choice (Elliott, 2004). The supremacy of EU law was effective in the UK only because an Act of Parliament said it should be. The logical conclusion of this reasoning is that Parliament, being sovereign, could also choose to reverse this decision by repealing the ECA 1972. This is precisely what happened following the 2016 referendum, with the enactment of the European Union (Withdrawal) Act 2018, which repealed the ECA 1972 and ended the supremacy of EU law in the UK. This ultimate act of reasserting domestic legislative control provides strong evidence that legal sovereignty was never truly ceded.
## Conclusion
In conclusion, the United Kingdom’s membership of the European Union undoubtedly placed Parliamentary sovereignty under significant strain. The practical effect of the ECA 1972 and the ruling in *Factortame* was that for nearly 50 years, EU law enjoyed a supreme status within the UK legal system, forcing courts to disapply conflicting Acts of Parliament. This was a clear departure from the traditional Diceyan model. However, the critical consideration is that this arrangement was based on Parliament’s own voluntary and intentional act in passing the ECA 1972. The supremacy of EU law was a condition of membership which Parliament accepted but could also, as the process of Brexit has demonstrated, ultimately reject. Therefore, while its legislative supremacy was politically and practically limited during its EU membership, Parliament’s ultimate legal sovereignty was never irrevocably lost.
## References
- Dicey, A. V. (1915) Introduction to the Study of the Law of the Constitution. 8th ed. Macmillan.
- Elliott, M. (2004) ‘United Kingdom: Parliamentary sovereignty under pressure’. International Journal of Constitutional Law, 2(3), pp. 545–627.
**Legislation**
- European Communities Act 1972
- European Union (Withdrawal) Act 2018
- Merchant Shipping Act 1988
**Case Law**
- Costa v ENEL (Case 6/64) [1964] ECR 585
- R v Secretary of State for Transport, ex p Factortame Ltd (No 2) [1991] 1 AC 603
