R (Miller and another) v Secretary of State for Exiting the European Union  EWHC 2768 (Admin)  2 WLR 583
(2) The principles of constitutional law: the sovereignty of Parliament and the prerogative powers of the Crown
(b) The sovereignty of the UK Parliament
20 It is common ground that the most fundamental rule of UK constitutional law is that the Crown in Parliament is sovereign and that legislation enacted by the Crown with the consent of both Houses of Parliament is supreme (we will use the familiar shorthand and refer simply to Parliament). Parliament can, by enactment of primary legislation, change the law of the land in any way it chooses. There is no superior form of law than primary legislation, save only where Parliament has itself made provision to allow that to happen. The ECA 1972 , which confers precedence on EU law, is the sole example of this.
21 But even then Parliament remains sovereign and supreme, and has continuing power to remove the authority given to other law by earlier primary legislation. Put shortly, Parliament has power to repeal the ECA 1972 if it wishes.
22 In what is still the leading account, Introduction to the Study of the Law of the Constitution , 8th ed (1915), by the constitutional jurist Professor AV Dicey, he explains that the principle of parliamentary sovereignty means that Parliament has:
"the right to make or unmake any law whatever; and, further, that no person or body is recognised by the law ... as having a right to override or set aside the legislation of Parliament." (p 38 of the 8th ed, the last edition by Dicey himself; and see chapter I generally.)
Amongst other things, this has the corollary that it cannot be said that a law is invalid as being opposed to the opinion of the electorate, since as a matter of law:
"The judges know nothing about any will of the people except in so far as that will is expressed by an Act of Parliament, and would never suffer the validity of a statute to be questioned on the ground of its having been passed or being kept alive in opposition to the wishes of the electors." (pp 57 and 72 of the 8th ed.)
23 The principle of parliamentary sovereignty has been recognised many times in leading cases of the highest authority. Since the principle is common ground in these proceedings it is only necessary to cite the speech of Lord Bingham of Cornhill in R (Jackson) v Attorney General  1 AC 262 , para 9: "The bedrock of the British constitution is ... the supremacy of the Crown in Parliament."
(c) The Crown's prerogative powers
24 The extent of the powers of the Crown under its prerogative (often called the royal prerogative) are delineated by UK constitutional law. These prerogative powers constitute the residue of legal authority left in the hands of the Crown. As Lord Reid said in Burmah Oil Co (Burma Trading) Ltd v Lord Advocate  AC 75 , 101: "The prerogative is really a relic of a past age, not lost by disuse, but only available for a case not covered by statute."
25 An important aspect of the fundamental principle of parliamentary sovereignty is that primary legislation is not subject to displacement by the Crown through the exercise of its prerogative powers. But the constitutional limits on the prerogative powers of the Crown are more extensive than this. The Crown has only those prerogative powers recognised by the common law and their exercise only produces legal effects within boundaries so recognised. Outside those boundaries the Crown has no power to alter the law of the land, whether it be common law or contained in legislation.
26 This subordination of the Crown (ie the executive government) to law is the foundation of the rule of law in the UK. It has its roots well before the war between the Crown and Parliament in the 17th century but was decisively confirmed in the settlement arrived at with the Glorious Revolution in 1688 and has been recognised ever since.
27 Sir Edward Coke reports the considered view of himself and the senior judges of the time in the Case of Proclamations (1610) 12 Co Rep 74 , 76 that "the King by his proclamation or other ways cannot change any part of the common law, or statute law, or the customs of the realm" and that "the King hath no prerogative, but that which the law of the land allows him".
28 The position was confirmed in the first two parts of article 1 of the Bill of Rights 1689 (1 Will & Mary, sess 2, c 2):
"Suspending power-That the pretended power of suspending of laws or the execution of laws by regall authority without consent of Parlyament is illegall.
"Late dispensing power-That the pretended power of dispensing with laws or the execution of laws by regall authoritie as it hath beene assumed and exercised of late is illegall."
29 The legal position was summarised by the Privy Council in The Zamora  2 AC 77 , 90:
"The idea that the King in Council, or indeed any branch of the Executive, has power to prescribe or alter the law to be administered by Courts of law in this country is out of harmony with the principles of our Constitution. It is true that, under a number of modern statutes, various branches of the Executive have power to make rules having the force of statutes, but all such rules derive their validity from the statute which creates the power, and not from the executive body by which they are made. No one would contend that the prerogative involves any power to prescribe or alter the law administered in Courts of Common Law or Equity."
These principles are not only well settled but are also common ground. It is therefore not necessary to explain them further.
(d) The power under the Crown's prerogative to make and unmake treaties
30 Another settled feature of UK constitutional law is that, as a general rule applicable in normal circumstances, the conduct of international relations and the making and unmaking of treaties on behalf of the UK are regarded as matters for the Crown in the exercise of its prerogative powers.
31 As we shall explain in more detail in examining the submission of the Secretary of State (see paras 77 and following), it is the Secretary of State's case that nothing has been done by Parliament in the ECA 1972 or any other statute to remove the prerogative power of the Crown, in the conduct of the international relations of the UK, to take steps to remove the UK from the EU by giving notice under article 50EU for the UK to withdraw from the EU Treaty and other relevant EU Treaties. The Secretary of State relies in particular on Attorney General v De Keyser's Royal Hotel Ltd  AC 508 and R v Secretary of State for Foreign and Commonwealth Affairs, Ex p Rees-Mogg  QB 552 ; he contends that the Crown's prerogative power to cause the UK to withdraw from the EU by giving notice under article 50EU could only have been removed by primary legislation using express words to that effect, alternatively by legislation which has that effect by necessary implication. The Secretary of State contends that neither the ECA 1972 nor any of the other Acts of Parliament referred to have abrogated this aspect of the Crown's prerogative, either by express words or by necessary implication.
(e) The effect of treaties on the domestic law of the UK
32 The general rule that the conduct of international relations, including the making and unmaking of treaties, is a matter for the Crown in exercise of its prerogative powers arises in the context of the basic constitutional principle to which we have referred at para 25 above, that the Crown cannot change domestic law by any exercise of its prerogative powers. The Crown's prerogative power to conduct international relations is regarded as wide and as being outside the purview of the courts precisely because the Crown cannot, in ordinary circumstances, alter domestic law by using such power to make or unmake a treaty. By making and unmaking treaties the Crown creates legal effects on the plane of international law, but in doing so it does not and cannot change domestic law. It cannot without the intervention of Parliament confer rights on individuals or deprive individuals of rights. .......
(3) The domestic effect of EU law and the ECA 1972
(a) The forms of EU law and the role of the Court of Justice of the European Union
37 As again the basic picture about how EU law operates is common ground, it is not necessary to give more than a brief explanation. Put very shortly, therefore, EU law as contained in the relevant treaties in some parts contains rights for individuals and in other parts creates law-making institutions which can legislate to make new legally binding norms of EU law from time to time. The principal forms of EU legislation are (1) directives, which require member states to introduce changes into their national law in conformity with what is set out in them, and (2) regulations, which have direct effect in the national law of member states. Where the treaties create rights for individuals, those rights may be enforced as directly effective in the national courts of member states. The same is true of rights set out in regulations. Also, some individual rights set out in directives are directly effective and may be relied upon in the national courts of member states.
38 These directly effective rights under EU law override even domestic primary legislation. Thus, for so long as EU law is accepted and applied by the national courts of a member state, it operates as a form of law which is in that sense superior to all domestic law.
39 The Community and EU Treaties created the European Court of Justice (now the Court of Justice of the European Union ("CJEU")) as the judicial body with authority to interpret and rule upon EU law. The CJEU does so both in proceedings brought by member states or by EU institutions and in cases referred to it by national courts under the reference procedure now contained in article 267FEU of the FEU Treaty . Controversial issues of EU law are to be referred by national courts to the CJEU for authoritative determination by that court, and national courts are obliged to apply EU law as interpreted by the CJEU.
40 These basic features of Community law were established well before the UK joined the European Communities in 1973. In particular, the superiority of EU law with direct effect was established in the well known judgments of the Court of Justice in NV Algemene Transport- en Expeditie Onderneming van Gend en Loos v Nederlandse Administratie der Belastingen (Case 26/62)  ECR 1 and Costa v Ente Nazionale per l'Energia Elettrica (ENEL) (Case 6/64)  ECR 585 . It has been affirmed many times since, for instance in the well known judgment in Amministrazione delle Finanze dello Stato v Simmenthal SpA (Case 106/77)  ECR 629 . Where EU law does not have direct effect but domestic legislation is introduced by a member state to comply with its obligations under a directive or other EU law, then as a matter of EU law a strong interpretive obligation applies so that the domestic legislation must be interpreted so as to be compatible with EU law wherever possible: Marleasing SA v La Comercial Internacional de Alimentación SA (Case C-106/89)  ECR I-4135 .
(b) The need for the ECA 1972 and its effect on the law of the UK
41 As a practical matter, by reason of the limits on its prerogative powers referred to at para 25 above, the Crown could not have ratified the accession of the UK to the European Communities under the Community treaties unless Parliament had enacted legislation. Legislation by Parliament was needed to give effect to EU law in the domestic law of the jurisdictions in the UK as was required by those treaties and as was necessary to give effect in domestic law to the rights and obligations arising under EU law.
42 It is common ground that only Parliament could create the necessary changes in national law to allow EU law to have the effect at the level of domestic law which the treaties required. As we have explained at para 1 above, this was done by the enactment of the ECA 1972 in contemplation of the UK becoming part of the European Communities by accession to the Community treaties so as to allow that to happen. If this legislation had not first been put in place, ratification of the treaties by the Crown would immediately have resulted in the UK being in breach of its obligations under them, by reason of the absence of provision for direct effect of EU law in domestic law.
(c) The ECA 1972 as a constitutional statute
43 In due course, the House of Lords confirmed in R v Secretary of State for Transport, Ex p Factortame Ltd  2 AC 85 that the ECA 1972 was effective, while it remained on the statute book, to give directly effective EU law superiority even over domestic primary legislation. By virtue of the ECA 1972 , the national courts give full effect to EU law as part of the domestic law applied by them.
44 As Laws LJ said in Thoburn v Sunderland City Council  QB 151 , para 62: "It may be there has never been a statute having such profound effects on so many dimensions of our daily lives." He described the ECA 1972 as a constitutional statute, having such importance in our legal system that it is not subject to the usual wide principle of implied repeal by subsequent legislation. Its importance is such that it could only be repealed or amended by express language in a subsequent statute or by necessary implication from the provisions of such a statute. Similarly, the ECA 1972 was described as one of a number of constitutional instruments by Lord Neuberger of Abbotsbury PSC and Lord Mance JSC in R (Buckinghamshire County Council) v Secretary of State for Transport  1 WLR 324 , para 207. ....................
(4) Categories of rights arising under the ECA 1972 and EU law
57 The parties presented a broad schematic account of three different categories of rights arising under EU law. For the purposes of analysis in this case it is helpful to use this scheme, although it is, of necessity, rather simplified. The analysis focuses on rights, but it is important to bear in mind that there are other substantial areas of EU law such as the schemes of regulation which take effect as part of the law of the UK.
(a) Category (i): rights capable of replication in the law of the UK
58 The first category of rights is those which are in principle capable of replication in domestic law if the UK does withdraw from the EU ("category (i) rights"). One example discussed at the hearing is the rights of workers under the Working Time Directive. Even if the UK had no *604 obligation under EU law to maintain such rights in domestic law, Parliament could choose to do so. The Secretary of State points to the fact that in many cases EU Directives and other EU laws have been implemented by domestic legislation, whether primary or subordinate, which will continue to apply, unless repealed, as free-standing enforceable domestic legislation when the UK leaves the EU. The Secretary of State also points to the Government's proposal for a Great Repeal Bill, according to which EU law rights would be re-enacted as ordinary rights in primary legislation.
59 We note that although the rights might be re-enacted using the same language, there would be some differences. For example, national courts would have no obligation to make, and individuals would not be able to seek, a reference to the CJEU to obtain an interpretation of the rights by that court. Of course, Parliament might choose not to replicate all existing EU law rights in domestic law.
(b) Category (ii): rights enjoyed in other member states of the EU
60 The second category of rights is those enjoyed by British citizens and companies in relation to their activities in other member states, as provided for by EU law, for example pursuant to rights of free movement of persons and of capital and rights of freedom of establishment ("category (ii) rights"). If a British citizen resides in another member state pursuant to EU rights of free movement, EU law requires the authorities and courts of that member state to respect and give effect to those rights. It also prohibits the authorities in the UK from placing impediments in the way of the exercise of such rights.
(c) Category (iii): rights that could not be replicated in UK law
61 The third category of rights is those which have an effect in the domestic law of the UK and which would be lost upon withdrawal from the EU and which could not be replicated in domestic legislation ("category (iii) rights"). Mr Eadie, on behalf of the Secretary of State, characterised these as rights flowing from the membership of "the EU club". These include the right to stand for selection or, later, for election to the European Parliament and the right to vote in such elections: see para 69 below. The right to seek a reference to the CJEU is another example. So is the right to seek to persuade the European Commission to take regulatory action in relation to matters within the UK, such as to investigate a violation of EU competition law or of EU environmental protection legislation occurring within the UK and grant a remedy in relation to it.
(d) The effect of withdrawal of the rights
62 The point of discussion of these categories of rights at the hearing was to examine the extent to which withdrawal of the UK from the relevant EU Treaties would affect rights in domestic law and would undo or modify the legal effects as brought about by Parliament through the enactment of the ECA 1972 . The claimants contend that Parliament by the ECA 1972 intended to give effect to each of these categories of right. They do so to emphasise the extent of the change which would be brought about by withdrawal pursuant to article 50EU , in order to reinforce their argument that the Crown could not effect such changes by the exercise of its prerogative powers. The Secretary of State maintains that whatever the extent of the changes upon withdrawal, Parliament has left the Crown with prerogative power to give notice under article 50EU . He also argues that the claimants exaggerate the extent and the degree to which categories (i) to (iii) were created by Parliament by the ECA 1972 . The Secretary of State accepts that category (iii) rights would be lost upon withdrawal, but he sought to minimise the extent of loss of category (i) rights and disputed that category (ii) rights were the product of enactment of the ECA 1972 .
63 Since the Secretary of State accepts that category (iii) rights include rights applicable in domestic law which are at least in part the product of the ECA 1972 and will be lost upon withdrawal from the EU, which is sufficient for the claimants' argument, these issues can be dealt with shortly.
64 As to category (i) rights, we consider that the claimants are correct in their submission that it is the ECA 1972 which is the principal legislation under which these rights are given effect in domestic law of the UK: and that it is no answer to their case to say that some of them might be preserved under new primary legislation, yet to be enacted, when withdrawal pursuant to article 50EU takes place. The objection remains that the Crown, through exercise of its prerogative powers, would have deprived domestic law rights created by the ECA 1972 of effect. We also consider that the removal of the ability to seek authoritative rulings of the CJEU regarding the scope and interpretation of such rights would itself amount to a material change in the domestic law of the UK.
65 As regards category (ii) rights, the prohibition against impediments to the exercise of these rights is part of EU law with direct applicability in the domestic law of the UK, as the Secretary of State accepts. However, the Secretary of State submits that the main content of these rights (say, the ability of a British citizen to rely on his or her rights of free movement when in another member state) is not the product of the ECA 1972 . Rather, it is the product of the operation of EU law in combination with the domestic law of that member state, just as the free movement rights of a national of that member state in England and Wales would be the product of EU law in combination with the domestic law of England and Wales. The Secretary of State says, further, that the effect of EU law on other member states for the benefit of British citizens was brought about by ratification of the relevant EU Treaties by the Crown on behalf of the UK on the international plane and the reciprocal ratification of those treaties by other member states, also on the international plane.
66 In a highly formalistic sense, this may be accurate. But in our view, it is a submission which is divorced from reality. As explained at paras 41-42 above, the enactment of the ECA 1972 was a necessary step before ratification of the relevant treaties could occur, as Parliament knew. As Parliament contemplated, it was only if it enacted the ECA 1972 (and then amended it to refer to later EU Treaties) that ratification of those treaties could occur. The reality is that Parliament knew and intended that enactment of the ECA 1972 would provide the foundation for the acquisition by British citizens of rights under EU law which they could enforce in the courts of other member states. We therefore consider that the claimants are correct to say that withdrawal from the EU pursuant to article 50EU would undo the category (ii) rights which Parliament intended to bring into effect, and did in fact bring into effect, by enacting the ECA 1972 . Although these are not rights enforceable in the national courts of the UK, they are none the less rights of major importance created by Parliament. Accordingly, the claimants are entitled to say that it would be surprising if they could be removed simply through action by the Crown under its prerogative powers. ......................
(c) The principle that the Crown cannot use its prerogative powers to alter domestic law
86 First, the powerful constitutional principle that the Crown has no power to alter the law of the land by use of its prerogative powers is the product of an especially strong constitutional tradition in the UK (and the democracies which follow that tradition: see for example the New Zealand decision in Fitzgerald v Muldoon  2 NZLR 615 , 622). It evolved through the long struggle (to which we have referred at para 26) to assert parliamentary sovereignty and constrain the Crown's prerogative powers. It would be surprising indeed if, in the light of that tradition, Parliament, as the sovereign body under our constitution, intended to leave the continued existence of all the rights it introduced into domestic law by enacting section 2(1) of the ECA 1972 (and, in the case of category (ii) rights, which it passed the ECA 1972 to bring into existence) subject to the choice of the Crown in the exercise of its prerogative powers as to whether to allow the Community treaties to continue in place or to take the UK out of them. As Lord Browne-Wilkinson put it in R v Secretary of State for the Home Department, Ex p Fire Brigades Union  2 AC 513 , 552E:
"It is for Parliament, not the executive, to repeal legislation. The constitutional history of this country is the history of the prerogative powers of the Crown being made subject to the overriding powers of the democratically elected legislature as the sovereign body."
87 In this context, it is also relevant to bear in mind the profound effects which Parliament intended to produce in domestic law by enactment of the ECA 1972 , which has led to its identification as a statute of special constitutional significance. The wide and profound extent of the legal changes in domestic law created by the ECA 1972 makes it especially unlikely that Parliament intended to leave their continued existence in the hands of the Crown through the exercise of its prerogative powers. Parliament having taken the major step of switching on the direct effect of EU law in the national legal systems by passing the ECA 1972 as primary legislation, it is not plausible to suppose that it intended that the Crown should be able by its own unilateral action under its prerogative powers to switch it off again.
88 Moreover, the status of the ECA 1972 as a constitutional statute is such that Parliament is taken to have made it exempt from the operation of the usual doctrine of implied repeal by enactment of later inconsistent legislation: see Thoburn's case  QB 151 , paras 60-64, and section 2(4) of the ECA 1972 . It can only be repealed in any respect if Parliament makes it especially clear in the later repealing legislation that this is what it wishes to do. Since in enacting the ECA 1972 as a statute of major constitutional importance Parliament has indicated that it should be exempt from casual implied repeal by Parliament itself, still less can it be thought to be likely that Parliament none the less intended that its legal effects could be removed by the Crown through the use of its prerogative powers. ....................
(e) Our conclusion as to Parliament's intention
92 Interpreting the ECA 1972 in the light of the constitutional background referred to above, we consider that it is clear that Parliament intended to legislate by that Act so as to introduce EU law into domestic law (and to create the category (ii) rights) in such a way that this could not be undone by exercise of Crown prerogative power. With the enactment of the ECA 1972 , the Crown has no prerogative power to effect a withdrawal from the Community treaties on whose continued existence the EU law rights introduced into domestic law depend (rights in categories (i) and (iii)) and on whose continued existence the wider rights of British citizens in category (ii) also depend. The Crown therefore has no prerogative power to effect a withdrawal from the relevant treaties by giving notice under article 50EU of the EU Treaty................ .