Chapter 5: The “supremacy principle”
71.Clause 5 provides that, for certain purposes, “the principle of the supremacy of EU law continues to apply after exit day”. In this way, the Bill seeks to elevate retained EU law by reference to the “supremacy principle”.
72.In this chapter we examine what we understand the Bill to mean by “the principle of the supremacy of EU law”, how it applies and why maintaining it post-exit is constitutionally flawed and will cause legal uncertainty. We conclude that the sensible policy aim behind perpetuating the supremacy principle can be achieved more effectively using domestic law principles and we recommend how this should be done.
The meaning and nature of the “supremacy principle”
73.The “supremacy principle”, as it is dubbed by clause 5 of the Bill, is a principle of EU law. In order properly to address its meaning and effects in relation to the UK, it is necessary to consider what it means in EU law and what effect it is given in the UK by domestic law.
74.The “supremacy principle” is not set out in the EU treaties. Rather, it is a concept that the CJEU developed early in the life of what became the EU. The principle is that when the domestic law of a Member State conflicts with EU law, it is EU law that takes priority. As the CJEU put it in Simmenthal, national courts, in such circumstances, must “apply [EU] law in its entirety”, disregarding “any provision of national law”—whenever it might have been enacted—“which may conflict with [EU law]”.35 From an EU law perspective, the principle is an uncompromising one: the CJEU has confirmed that EU law has priority over all forms of domestic law, including provisions found in Member States’ constitutions and in constitutional bills of rights.36
75.However, it is important to examine how the principle applies in the UK as a result of membership of the EU. In the Thoburn case,37 it was argued on behalf of one of the parties that EU law had primacy over UK law “not by virtue of any principle of domestic constitutional law, but by virtue of principles of [EU] law”—including the “supremacy principle”—already established by the CJEU in cases like Simmenthal. This argument suggested that EU law had become “entrenched” in the UK, and that the traditional idea of parliamentary sovereignty was now of only “historical, but not actual, significance”. However, the court rejected these arguments. Lord Justice Laws, giving the judgment, said that the UK Parliament remained sovereign and that EU law had force in the UK only because Parliament, by enacting the European Communities Act 1972, had allowed it to do so. Therefore the far-reaching nature of the claims made by the “supremacy principle” are of limited consequence in the UK: instead, what matters is what domestic law says about whether, and if so to what extent, EU law has priority over UK law.
76.This analysis is supported both by higher judicial authority and by Parliament itself. In the HS2 case, Lord Reed said that questions about the extent of EU law’s priority over domestic law “cannot be resolved simply by applying the doctrine developed by the Court of Justice of the supremacy of EU law, since the application of that doctrine in our law itself depends upon the 1972 Act.”38 This is consistent with Parliament’s own view of matters. In section 18 of the European Union Act 2011, Parliament confirmed that EU law has effect in the UK “only by virtue of” the ECA.39 Therefore, what the present Bill calls “the principle of the supremacy of EU law” only applies in the UK because, and to the extent that, Parliament has so provided in the ECA. Indeed, in the HS2 case, the Supreme Court said that on a proper reading of the ECA, Parliament may not have granted EU law priority over all domestic law, and that certain fundamental principles of domestic law would continue to take precedence over EU law.
Clause 5: intended effect
77.Clause 5(1) of the Bill states: “The principle of the supremacy of EU law does not apply to any enactment or rule of law passed or made on or after exit day.” However, clause 5(2) continues: “Accordingly, the principle of the supremacy of EU law continues to apply on or after exit day so far as relevant to the interpretation, disapplication or quashing of any enactment or rule of law passed or made before exit day.”
78.According to its explanatory notes to the Bill, the Government’s intention is that these provisions will operate as follows:
- The “supremacy principle” will not operate in relation to legislation that is enacted on or after exit day. As such, post-exit domestic legislation will not be prevented by the “supremacy principle” from having priority over any retained EU law.
- However, the “supremacy principle” will operate in relation to legislation that is enacted prior to exit day. Thus, any EU-related law to which the “supremacy principle” applies will take priority over all pre-exit domestic law, including pre-exit Acts of Parliament.
79.During UK membership of the EU, EU law takes priority over domestic law. This is well-recognised and it would be destabilising if, upon exit, retained EU law’s status radically changed such that pre-exit domestic law could prevail over it. However, while we support the policy aims that underpin clause 5(1) and (2), we consider—for reasons that we explain in the next section—that the way in which those provisions purport to give effect to these aims is conceptually flawed, sits uncomfortably with the doctrine of parliamentary sovereignty and is a potential source of legal confusion.
Clause 5: three problems
80.There are three major problems with clause 5 as it stands. The first two problems suggest that clause 5 should be clarified. However, the third problem leads us to conclude that the whole approach adopted in clause 5(1) and (2) is misconceived, and that an entirely different approach is required if the Bill is to secure its overarching objectives of legal continuity and certainty.
The scope of the “supremacy principle”
81.Clause 5 refers to “the principle of the supremacy of EU law”. This raises the question of exactly what law that principle, to the extent that it is intended to continue to apply post-exit, is supposed to protect.40 In particular, it is unclear whether it is intended to protect all retained EU law or only some types of retained EU law. On this point, the Solicitor General told us that:
“supremacy as retained under the Bill will plainly not apply to every aspect of retained EU law. For example, domestic regulations that have been made to implement EU law do not have a supreme status after exit day that they did not have before, so there is no change there … We all know … the principle of what supremacy means: it is, if you like, a hierarchy in which particular aspects of law, particularly directly applicable EU law, have to take precedence over pre-exit domestic law in the event of a conflict. That will carry on.”41
82.The Solicitor General appears to take the view that retained EU law will benefit from the “supremacy principle” (in respect of pre-exit domestic law) only if it corresponds to pre-exit EU law that itself benefitted from the “supremacy principle”. In very broad terms, this suggests that retained direct EU legislation under clause 3 and directly effective EU law domesticated by clause 4 should benefit from the post-exit “supremacy principle” under clause 5. However, it suggests that EU-derived domestic legislation under clause 2 should not benefit from the post-exit “supremacy principle” because it, unlike the underlying EU law to which it gives effect, did not benefit from that principle pre-exit. We consider this to be a sensible approach, not least because it corresponds to the current position as regards EU law, and thus accords with the Bill’s objective of securing legal continuity. However, none of this is clear from the face of the Bill. Indeed, the Bill says nothing about the types of retained EU law to which the “supremacy principle” is intended to apply following exit.
83.It is constitutionally unacceptable for the Bill to be ambiguous as to what retained EU law the “supremacy principle” will apply. It is insufficient for the Solicitor General to suggest that there is a shared assumption as to what the “supremacy principle” means and that it will therefore function in the Bill as the Government wishes it to. If references to the “supremacy principle” were to be preserved in the Bill, then clause 5 should be amended to set out clearly the intended scope of the principle.
The “supremacy principle” and the common law
84.It is not clear from clause 5 what types of retained EU law the “supremacy principle” is intended to benefit. A further difficulty is that it is not clear when the principle is intended to bite upon other forms of domestic law (i.e. forms of domestic law that are intended to yield to retained EU law because of the “supremacy principle”). It is clear that the “supremacy principle” is intended to give (at least some) retained EU law priority over pre-exit legislation. However, the position is less clear when account is taken of clause 5(2), which refers not only to pre-exit “enactments” but also to any “rule of law passed or made before exit day”.
85.The Solicitor General told us that the reference in clause 5(2) to any “rule of law” is intended to ensure that the “supremacy principle” applies not only to legislation but also to the common law:
“the principle of supremacy will continue to apply in so far as it is relevant to the interpretation or disapplication of any enactment or rule of law—our wording, “rule of law”, has attracted a bit of criticism, but we are mindful of the fact that not all our law is in statute and there are common-law principles and other aspects that need to be embraced by this legislation—that is passed before the day of exit.”42
86.The application of the “supremacy principle” to common law “made before exit day” is, however, problematic: the common law emerges and evolves, unlike legislation that definitively takes effect at a certain point in time. This raises questions about the extent to which judges who articulate “new” common law rules or principles are in fact making new law or are declaring the common law as it has always been (whether or not it was previously so appreciated or articulated) and whether or not the supremacy principle would apply in such instances. Therefore it is difficult to say, in respect to any given rule or principle of common law, that it was “made” on a given date. As a result, the application of clause 5(2) to the common law is likely to be far from straightforward.
87.If references to the “supremacy principle” were to be preserved in the Bill, then clause 5 would need to be amended to provide courts and others with suitable guidance for the purpose of determining whether a rule of the common law should be taken to have been “made” before or after exit. Providing such guidance is unlikely to be a straightforward matter. However, we do not make any specific proposals about what the form or content of any such guidance should be, because we consider, for reasons set out below, the notion of retaining the “supremacy principle” to be misconceived.
A post-exit “supremacy principle”: conceptual flaws
88.We find it impossible to see in what sense “the principle of the supremacy of EU law”, set out in clause 5, could meaningfully apply in the UK once it has left the EU. Following exit, there will be no “EU law” within the domestic legal system, as a central purpose of the Bill is to excise all EU law from the UK legal system. Most EU law that exists immediately prior to exit will remain within the domestic system in the form of retained EU law as a result of the Bill, however, retained EU law will not be EU law: it will be domestic law. As a result, there is no meaningful sense in which “the principle of supremacy of EU law” can apply to retained EU law, given that the latter is not EU law. As Richard Gordon QC told us, “the whole concept of EU supremacy is not an easy one when there is no EU law, because you have just obliterated it on exit day.”43
89.We consider that the notion of maintaining the “supremacy principle” following exit amounts to a fundamental flaw at the heart of the Bill. We do not consider that clause 5 clearly operates to bestow “supremacy” on retained EU law once exit day arrives. The “supremacy” of EU law will cease to apply when the UK leaves the EU and Parliament repeals the ECA. Retained EU law, being domestic law, cannot benefit from “the principle of the supremacy of EU law”.
90.This issue cannot be simply resolved by amending the Bill to state that “retained EU law”, rather than “EU law”, has supremacy. The “supremacy principle” is the creation of the CJEU and a principle of EU law. It has meaning and application only in relation to EU law, and to seek to graft that EU law principle onto a legislative scheme whose explicit purpose is to remove EU law from the UK legal system and replace it with domestic law risks confusion and places legal certainty in jeopardy. It does not make sense, either as a matter of language or as a matter of constitutional principle.
91.The “supremacy principle” is alien to the UK constitutional system: not only did it originate outside that system, it also sits uncomfortably with established constitutional principles, most notably the doctrine of parliamentary sovereignty. If the cumbersome device of seeking to maintain the “supremacy principle” post-exit were the only means of seeking to give retained EU law priority over pre-exit domestic legislation, then attempting to leverage such an approach might be comprehensible, if not necessarily effective. However, as we set out below, we consider that the requisite status can be given to retained EU law in a way that is more straightforward and which accords with UK constitutional principles.
An alternative approach
92.Taking into account the text of the Bill, the explanatory notes and the Solicitor General’s evidence to us, our understanding is that clause 5(1) and (2) seeks to give retained direct EU law priority over pre-exit, but not post-exit, domestic law.
93.We consider the objective of giving retained direct EU law priority over pre-exit, but not post-exit, domestic law to be a sensible one. However, we regard the means employed by clause 5 in seeking to deliver that object to be fundamentally flawed. In our view, the way to deliver this objective would be to put to one side the concept and language of supremacy, and to focus on the domestic legal status of retained direct EU law. We recommend that retained direct EU law should be made to prevail over pre-exit domestic law by providing in the Bill that retained direct EU legislation under clause 3 and all law that is converted into domestic law by clause 4 is to be treated as having the status of an Act of the UK Parliament enacted on exit day.
94.No equivalent provision needs be made in relation to EU-derived domestic legislation under clause 2: such legislation already has the status of either primary or secondary legislation in domestic law, and already has a domestic date of enactment. Legal continuity will best be served by treating EU-derived domestic legislation as what it has always been: namely, domestic primary or secondary legislation in the ordinary sense.
95.This approach has a number of advantages. First, it would secure the priority of retained direct EU law over pre-exit domestic legislation without needing to attempt the logically difficult, if not impossible, task of treating retained direct EU law as benefitting from the “principle of the supremacy of EU law”. Instead, it would prevail, under orthodox constitutional doctrine, by virtue of a combination of two factors: its deemed legal status (i.e. an Act of Parliament) and the date of its conceptual “enactment” (i.e. exit day). Like any (actual) Act of Parliament, retained direct EU law would thus prevail over earlier inconsistent legislation, while subsequent inconsistent legislation would prevail over it.
96.Second, this proposal accords with the central recommendation made in the previous chapter: namely, that all retained direct EU law should be regarded as primary legislation. In this way, potential difficulties created by the Bill as it is currently drafted would be avoided. For instance, as presently drafted, the Bill envisages that a Minister might use clause 17 to designate a given piece of retained direct EU law as secondary legislation, yet clause 5 would continue to accord to that secondary legislation “supremacy” over pre-exit domestic legislation, including pre-exit Acts of Parliament. The resulting notion of secondary legislation that has “supremacy” over primary legislation risks uncertainty and confusion, introducing a conceptual innovation fundamentally at odds with the doctrine of parliamentary sovereignty as currently understood. Under our proposal, however, no such possibility arises: all retained direct EU law is to be treated as having the status as an Act of Parliament enacted on exit day. All questions about its relationship with other legislation will fall to be answered using the established principles of domestic law that condition the relationship between a given Act of Parliament and other domestic laws.
97.Third, the difficulties identified above concerning the operation of the “supremacy principle” with respect to common law “made before exit day” would no longer arise, because there would be no question of the “supremacy principle” applying. Instead, the relationship between retained direct EU law and the common law would be set by established principles that govern the relationship between Acts of Parliament and the common law.
98.Fourth, and more generally, our approach accords with the principles and traditions of the UK constitution. The EU “supremacy principle” is one that has no domestic constitutional counterpart, and there is no need to retain it once the UK leaves the EU. Moreover, excising the “supremacy principle” from domestic law is wholly consistent with the thrust and purpose of the present Bill. Although the Bill perpetuates in domestic law a vast body of what was EU law, the crucial point is that it turns what was EU law it into domestic law. It is therefore to domestic principles of constitutional law, not the EU law principle of “supremacy”, to which Parliament should look in seeking to stipulate what the legal status and effects of retained EU law—a new body of domestic law—will be.
99.Treating retained EU law saved by clauses 3 and 4 as primary legislation would avoid the need for any “supremacy principle”, and would greatly simplify its constitutional position by ascribing to it a status consistent with the doctrine of parliamentary sovereignty. It would also complete the task of excising EU law from domestic law by making clear that retained direct EU law is, after exit day, domestic rather than EU law, subject only to the doctrines and principles of the UK constitution and not in any way contingent for its status upon the externally-derived constitutional doctrines of the EU.
The “supremacy principle” and changes to relevant law
100.Clause 5(3) envisages that the “supremacy principle” may apply to pre-exit domestic legislation even if such legislation is modified on or after exit day, provided that “the application of the [supremacy] principle is consistent with the intention of the modification”. This suggests that pre-exit legislation does not necessarily, when modified post-exit, become post-exit legislation, thereby removing it from the scope of the operation of the “supremacy principle”. However, pre-exit legislation that is modified will continue to be regarded as pre-exit legislation—and so subject to the “supremacy principle”—only if that is “consistent with the intention of the modification”.
101.If our principal recommendation, set out above, is adopted, clause 5(3) will need to be removed from the Bill, as no questions will arise about the circumstances in which the “supremacy principle” does and does not apply. However, if that recommendation is not adopted, then clause 5(3) will need to be amended, since it is insufficiently clear as it stands, and this risks creating legal uncertainty. Specifically, the phrasing of subsection (3)—“consistent with the intention of the modification”—is problematic, as it is not clear how such an intention or its absence would be discerned.
102.A further connected problem arises as to whether “supremacy principle” is intended to protect only “retained EU law” or whether it continues to apply to retained EU law once it has been modified. The definition of “retained EU law” in clause 6(7) suggests that retained EU law does not lose its status as such merely because it has been modified. However, it is difficult to see why retained EU law that has been substantially amended, and bears little resemblance to the EU law from which it originated, should continue to benefit from the “supremacy principle” merely because it began life as EU law.
103.If the “supremacy principle” were to continue to feature in the Bill, clause 5(3) would need to be amended to clarify the extent to which retained EU law can be modified while retaining the benefit of that principle, and to clarify in what circumstances the modification of pre-exit domestic law would be such as to turn it into post-exit domestic law that is no longer vulnerable to the operation of the “supremacy principle”. However, in the light of our principal recommendation, that retained direct EU law should be treated as primary legislation enacted on exit day (para 93), we make no detailed recommendations on these matters.
35 Case 106/77 Amministrazione delle Finanze dello Stato v Simmenthal SpA [1978] ECR 629. See also Flaminio Costa v ENEL [1964] ECR 585.
36 Case 11/70 Internationale Handelsgesellschaft mbH v Einfuhrund Vorratsstelle für Getreide und Futtermittel [1970] ECR 1125
39 Or by virtue of any other UK legislation that accords domestic effect to EU law. European Union Act 2011, section 18.