The UK has facilitated the supremacy of EU law through enacting the European Communities Act 1972. However, the UK has accepted EU law is supreme in relation to all domestic laws. Jurisdictions like Germany have a narrower approach. Germany allows for the primacy of EU law only where EU law adequately protects constitutional rights enshrined in the German Constitution. The UK has made provision for supremacy of EU law in certain circumstances after the UK exits the EU on 31 October 2019. This is to be welcomed as the principle of supremacy will remain important after exit day.
UK’s acceptance of supremacy
In order for EU law to work it needs to have priority in the legal system of the Member States. The doctrine of supremacy means where there is a conflict between EU law and domestic law, then EU law wins. Supremacy is not mentioned in the EU Treaties. It was created by the CJEU. The principle of supremacy was highlighted in the case of Costa v ENEL. A dispute arose as to whether Italian Courts were obliged to apply domestic legislation or if a preliminary ruling from the CJEU would have primacy. The CJEU held that ‘community law must prevail over conflicting rules of national law, even if enacted subsequently to the Community rules.’ Supremacy was bolstered further when the CJEU held that EU law was supreme even against domestic law was passed that conflicted with the previous EU norms. In Internationale Handelsgesellschaft the CJEU held that EU law took primacy over many types of domestic law including constitutional laws. The net effect is that the CJEU confirms that EU law is supreme in almost all circumstances.
Supremacy in the UK
Legal systems have to manage the tension between EU supremacy and their claim to national supremacy. Different Member States have had varying levels of difficult in accepting the principle of supremacy given that the Member States have different constitutional traditions (Craig 2003).The difficulty with EU law primacy in the UK is that the UK constitution places great importance on the principle of parliamentary sovereignty. Essentially, Parliament has the right to make or unmake any law (Wade 1955).
The UK adopts a dualist approach to the EU-domestic relationship. This means that EU law only has effect when enacted by a domestic Act of Parliament. The European Communities Act 1972 was the domestic Act adopted by the UK. The House of Lords considered the approach courts must take when there is a conflict between EU law and domestic law in Factortame II. There was a direct conflict between an EU Treaty and domestic law (Merchant Shipping Act 1988). The Lords held that the European Communities Act 1972 provided for the supremacy of EU law where there is a conflict with UK law. In effect, courts must ‘disapply’ domestic legislation where such conflict exists. Lord Bridge held that it was the duty of a national court to choose EU law over domestic law. This appears to be a radical reformulation of the notion of parliamentary sovereignty (Wade 1996). However, some scholars (Elliot 2010) believe that national laws still have priority because the UK could withdraw from the EU anytime by repealing the 1972 Act.
Further, in Miller v Secretary of State for Exiting the EU (2017) the Supreme Court concluded that a court’s duty to disapply domestic legislation did not apply to legislation that alters the constitutional status of EU institutions or EU law. Therefore, the duty to disapply is not absolute. This argument was further bolstered by the European Union Act 2011 which declared that EU law only took effect in the UK because of the continued existence of the 1972 Act. This is not an entirely convincing argument. While it was theoretically possible to repeal the 1972 Act – there was no political appetite to do so until after 2014 when the momentum for Brexit gathered pace. The UK courts are able to reconcile EU law with parliamentary sovereignty as the UK adopts a dualist approach to implementing law into its domestic legal framework.
What about what other Member States think other than the UK?
Germany: At first, the highest German court refused to recognize supremacy of EU law over German constitutional law. In Solange I the court held that where there was a conflict between EU law and domestic constitutional law then the constitutional law was preferred. In Solange II the German Constitutional Court softened its position. It concluded that where there was a conflict between German constitutional law and EU law the domestic court would not interfere as long as EU law provided equal protections. As the CJEU had developed a fundamental rights doctrine the German Constitutional Court could no longer give primacy to domestic law that conflicted with EU law as the rights doctrine could protect the rights from the German constitution (Frowein 1988). However, in Brunner v The European Treaty  the German Court stated that it will intervene to assess the compatibility of EU law with the German constitution and to decide questions on the extent of the scope of Community competence. The effect of Solange II is that German Courts will not control whether EU law infringes domestic law where EU law protections are in place. This shows that Germany will defer to EU law under certain conditions. However, these conditions are narrower than those in the UK. Whereas the UK, through the 1972 Act, gives primacy to EU law, Germany gives primacy to EU law under strict conditions.
Section 1 of the European Union (Withdrawal) Act 2018 will repeal the European Communities Act 1972 on “exit day”. In the short-term following “exit day”, much of domestic law made under s.2 of that Act, and much EU law having direct effect, will be “frozen” in UK law until new domestic legislation is passed. However, is unclear when ‘exit day’ will actually take place: the European Union Council Decision of 10 April 2019 extends the pre-Brexit period under art.50(3) TEU until 31 October 2019. Given the political uncertainty as to whether the UK will actually leave on 31 October. While the UK has a new Prime Minister determined to leave on the 31 October, this is still not a certainty.
Section 5(1) of the Withdrawal Act 2018 states that the supremacy of EU law does not apply to laws passed on or after exit day. However, s. 5(2) states that EU supremacy will continue to apply on or after exit day so far as relevant to the interpretation or disapplication of laws passed or made before that day. Elliot and Tierney (2019) support the idea that retained EU supremacy should exist in relation to pre-Brexit domestic law. However, the Constitution Committee (2008) believe that the term ‘supremacy’ in this context is problematic. They state that supremacy in its current form could not survive once the UK left the EU. Supremacy of EU law cannot apply to retained EU law as it is not EU law in the narrow sense. Retained law is essentially domestic law and therefore this limits any conflict with the notion of parliamentary sovereignty (Elliot and Tierney 2019).
However, the government have stated that supremacy will survive to an extent but in a diminishing way (Lord Callanan 2018). Parliament will pass legislation in different areas that means supremacy of EU law, or retained EU law, will reduce very quickly. The task of replacing EU law with domestic law has been described as a ‘legal undertaking of a type and scale that is unique and unprecedented’ (Constitution Committee 2018). Approximately 20,000 domestic laws have been derived from EU law (Miller 2017). Therefore, it is right that the withdrawal legislation deals with the issue of supremacy as it will figure in the constitutional landscape after the UK withdraws from the EU.
The UK courts have embraced the idea of EU supremacy more than the courts of other jurisdictions such as Germany. As the UK prepares to withdraw from the EU it is right that the principle of supremacy is dealt with in the withdrawal legislation. Supremacy will remain important for retained legislation but this mode of supremacy is not the supremacy envisaged when the UK first passed the 1972 Act. Nevertheless, it is right that the principle of supremacy has been dealt with by withdrawal legislation as the issue of supremacy will not extinguish on exit day.