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EU Law in the UK Constitutional Framework for SQE1

Part of our SQE1 Constitutional and Administrative Law guide → View the full SQE1 Constitutional and Administrative Law guide

13 Apr 2026

EU law occupied a unique place in the UK constitution, with direct effect and supremacy over conflicting domestic law. Understanding Factortame, the European Union (Withdrawal) Act 2018 and retained law is essential for SQE1.

EU Law in the UK Constitutional Framework for SQE1

Constitutional & Administrative Law > EU Law in the UK Constitutional Framework

EU law fundamentally reshaped the UK constitution during the UK's membership of the European Union (1973-2020). Understanding how EU law operated, the principle of supremacy, and the constitutional changes following withdrawal is important for SQE1, particularly for understanding how parliamentary sovereignty was temporarily qualified and how it was reasserted.

What is EU Law's Role in the UK Constitution for SQE1?

Candidates often assume Factortame permanently overrode parliamentary sovereignty — a fundamental misunderstanding that loses marks on SQE1. During EU membership, EU law occupied a unique constitutional position. It was incorporated into UK law by the European Communities Act 1972, which gave effect to EU law in domestic law. EU law had two key characteristics: direct effect (it could be relied on directly in UK courts) and supremacy (conflicting UK law was disapplied).

Following Brexit and the European Union (Withdrawal) Act 2018, the UK is no longer an EU member, but understanding the constitutional principles and how the UK reasserted sovereignty is essential for SQE1.

Key Principles for SQE1

  • The European Communities Act 1972: this Act incorporated EU law into UK domestic law. Section 2(1) made directly applicable EU law (regulations, decisions) part of UK law automatically. Section 2(4) required all UK legislation to be interpreted and applied compatibly with EU law. This was the constitutional basis for EU law supremacy in the UK.

  • Direct Effect: EU regulations and decisions had direct effect, meaning they could be relied on directly in UK courts without further implementation. EU directives had direct effect only in vertical relationships (between an individual and the state), not in horizontal relationships (between private parties) — this is an important limitation.

  • Supremacy of EU Law: in R v Secretary of State for Transport, ex parte Factortame (No 2) [1991], the House of Lords held that where UK law conflicted with EU law, the UK law must be disapplied (set aside). This appeared to challenge parliamentary sovereignty, but the House of Lords reasoned that Parliament had authorised this through the European Communities Act 1972. Parliament had voluntarily agreed to the supremacy of EU law for matters within EU competence. This principle is essential for understanding how parliamentary sovereignty and the rule of law operate in the modern UK constitution.

  • The Factortame Principle: this established that courts could review whether UK legislation breached EU law and could disapply conflicting provisions. Importantly, this was not a permanent override of sovereignty — it was conditional on the European Communities Act 1972 remaining in force.

  • Limits to EU Competence: EU law only applied to matters within EU competence. Matters not transferred to the EU (such as criminal law, most family law, tax law) remained entirely within UK competence, though the EU's competence expanded significantly over time through successive treaties.

  • The Charter of Fundamental Rights: the EU's Charter of Fundamental Rights became binding on EU institutions and member states when implementing EU law (as confirmed by the Treaty of Lisbon, 2007). This provided human rights protection in the EU context, though the UK negotiated a limited application of the Charter.

  • The European Union (Withdrawal) Act 2018: this Act repealed the European Communities Act 1972 and converted retained EU law into domestic law. "Retained EU law" includes directly applicable EU law that was in force at the moment of withdrawal (treated as made under UK law) and EU law that had been implemented by UK regulations (kept in place). The Act also preserved the effect of EU case law and principles as understood at the time of withdrawal.

  • Retained Law and Amendments: retained EU law can be amended or repealed by UK Parliament and has no special status — it is domestic law and can be changed like any other statute. However, some retained law is protected pending review.

  • Supremacy Reversed: following the 2018 Act, EU law no longer has supremacy. Where retained EU law conflicts with UK legislation passed after 1 January 2020 (the withdrawal date), the later UK legislation prevails. This is orthodox parliamentary sovereignty.

  • The European Union (Future Relationship) Act 2020: this Act gave effect to the Trade and Cooperation Agreement between the UK and EU. It is primarily a foreign affairs matter, but has implications for retained law and the continued operation of some EU-law-like principles (such as mutual recognition in limited areas).

  • Current EU-UK Relationship: post-withdrawal, the UK is bound by the Trade and Cooperation Agreement, which provides a framework for trade, security cooperation, and mutual recognition in certain areas. However, there is no supremacy of EU law, and the UK is not bound by new EU legislation or CJEU case law (though previous CJEU decisions remain relevant as historical authority).

Exam tip

The biggest SQE1 trap is confusing the EU law era with post-withdrawal law. If a question involves pre-2020 events or EU law concepts, know that EU law had supremacy and direct effect. If it involves post-2020 events, understand that retained law is domestic law without special status. Also, remember that Factortame did not permanently override parliamentary sovereignty — Parliament authorised it through the European Communities Act and later reversed it through the Withdrawal Act. This nuance is important for understanding the constitutional principle.

How This Appears in SQE1 Questions

SQE1 questions involving EU law typically present scenarios from before the 2020 withdrawal date or ask about the constitutional principles demonstrated by the Factortame case and EU supremacy. This is a classic SQE1 trap where understanding the limits of the Factortame principle is key. Questions may also ask about retained law or conflicts between retained law and UK legislation.

Example scenario: A UK statute conflicts with retained EU law. How should courts interpret the statute? The answer depends on when the conflicting UK legislation was passed. If before 1 January 2020, courts would have applied EU law supremacy (disapplying the UK provision). If after 1 January 2020, the UK legislation prevails.

Constitutional principle: Factortame demonstrates that parliamentary sovereignty is supreme. Parliament can agree to limit its own sovereignty (through the European Communities Act), but Parliament can also reassert that sovereignty (through the Withdrawal Act). This shows sovereignty is not absolute in the sense of being permanent — a Parliament cannot bind its successors. The Withdrawal Act shows how this works in practice.

This is a classic SQE1 trap: candidates assume Factortame permanently changed UK constitutional law. It did not — it operated only within the framework established by Parliament, which Parliament later changed.

Common Mistakes Students Make

  • Assuming Factortame permanently overrode parliamentary sovereignty — it did not; it operated within the framework established by Parliament through the European Communities Act
  • Forgetting that EU law supremacy was conditional on the 1972 Act remaining in force
  • Missing that the Withdrawal Act restored parliamentary supremacy by converting retained law into ordinary domestic law
  • Assuming retained EU law has special status — it does not; it is domestic law and can be amended like any statute
  • Confusing EU law from the membership era with retained law — they operate differently
  • Assuming current UK law is still bound by EU law — it is not (except as retained law, which has no special status)
  • Missing that the Trade and Cooperation Agreement is a trade deal, not constitutional incorporation of EU law
  • Forgetting that CJEU case law after withdrawal is not binding on UK courts — previous decisions remain relevant as authority, but new EU case law does not apply

Quick Summary

  • The European Communities Act 1972 incorporated EU law into UK domestic law with supremacy and direct effect
  • Factortame established that conflicting UK law must be disapplied when EU law applies
  • This was not a permanent override — Parliament had voluntarily agreed to it through the 1972 Act
  • The European Union (Withdrawal) Act 2018 repealed the 1972 Act and converted retained EU law into domestic law
  • Retained EU law has no special status and can be amended or repealed by UK Parliament
  • The principle of supremacy no longer applies — post-withdrawal UK legislation takes precedence
  • The UK's relationship with the EU is now governed by the Trade and Cooperation Agreement
  • Understanding the pre- and post-withdrawal positions is essential for SQE1

Want to test this now? Try a few SQE1-style questions below before moving on.

Test Yourself

Test yourself

Quick check questions based on this article.

Question 1

Scenario

A solicitor is advising a client on a claim against the UK government. The client argues that a retained EU regulation confers a right to compensation for losses suffered as a result of a government decision. Before Brexit, the client could have relied on the Francovich principle - the EU law principle that a member state may be liable in damages for sufficiently serious breaches of EU law. The client's losses arose from a government decision made in 2024. The client contends that the Francovich principle continues to apply to claims arising under retained EU law, because the European Union (Withdrawal) Act 2018 preserved the body of EU law in domestic form. The government argues that the Francovich principle does not apply to post-Brexit claims and that the client must instead bring any claim under domestic principles of judicial review or private law. The solicitor is aware that the Retained EU Law (Revocation and Reform) Act 2023 made changes that may affect the availability of Francovich damages. The client's business partner, who is a retired judge, has informally expressed the view that the claim is strong. The solicitor is mindful that this does not constitute formal legal advice.

Which of the following most accurately describes the availability of Francovich damages for the client's claim?

Question 2

Scenario

A food manufacturer has been producing a range of organic sauces since 2015. Before the UK's withdrawal from the European Union, the company's labelling complied with EU Regulation 834/2007 on organic production and labelling. Following the end of the transition period on 31 December 2020, the company continued to use the same labelling. A trading standards officer inspects the company's premises and raises concerns about whether the labelling remains compliant with domestic law. The company's director seeks legal advice on the status of the EU regulation in domestic law following Brexit. The director recalls that the company had to make changes to its export documentation after Brexit, but she is unsure whether the labelling standards themselves have changed. The company exports 40% of its production to EU member states, though this is not relevant to the domestic labelling question. The company's solicitor has not previously advised on retained EU law matters. The solicitor researches the position and identifies that the European Union (Withdrawal) Act 2018 made provision for the treatment of EU law in the UK after the transition period ended.

Which of the following best describes the status of EU Regulation 834/2007 in UK domestic law following the end of the transition period?

Question 3

Scenario

A junior solicitor is preparing a briefing note for a senior partner on the transition period following the United Kingdom's departure from the European Union. The junior solicitor recalls that the transition period was established by an agreement between the UK and the EU. During the transition period, the junior solicitor understands that EU law continued to apply in the United Kingdom. The senior partner has asked specifically about the end date of the transition period. The junior solicitor checks the Withdrawal Agreement and the relevant domestic legislation. The firm's offices are located near Chancery Lane in London. The junior solicitor has been qualified for approximately seven months. She notes that the transition period was given effect in domestic law by the European Union (Withdrawal Agreement) Act 2020.

On what date did the transition period end, after which EU law ceased to apply in the United Kingdom?

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