R (On The Application Of (1) Gina Miller (2) Deir Tozetti Dos Santos) (Claimants) v Secretary Of State For Exiting The European Union (Defendant) & (1) Grahame Pigney & Ors (2) AB, KK, PR & Children (Interested Parties) & George Birnie & Ors (Intervener)
The Government did not have power under the Crown's prerogative to give notice pursuant to TEU art.50 for the UK to withdraw from the EU.
The claimants applied for judicial review of the Government's intention to give notice pursuant to TEU art.50 for the UK to withdraw from the European Union.
The UK joined the European Communities in 1973. The European Communities Act 1972 gave effect to Community law in the UK. The EC subsequently became the European Union. A referendum took place in June 2016 under the European Union Referendum Act 2015. The result of the referendum was that the UK should leave the EU. Withdrawal was governed by art.50. It was common ground that withdrawal from the EU would have profound consequences in terms of changing domestic law in each of the UK jurisdictions.
The claimants submitted that it was a fundamental principle that the Crown's prerogative powers could not be used by the executive government to diminish or abrogate rights under UK law unless Parliament had given authority, expressly or by necessary implication from the terms of an Act of Parliament.
The secretary of state contended that Parliament could choose to leave, or not to abrogate, prerogative power in the hands of the Crown, even if its use resulted in a change to common law and statutory rights, and that no express words could be found in the 1972 Act or any other statute abrogating the prerogative powers in relation to the EU treaties.
(1) The most fundamental rule of UK constitutional law was that the Crown in Parliament was sovereign and that legislation enacted by the Crown was supreme. Parliament could, by enactment of primary legislation, change the law. There was no superior form of law, except where Parliament had made such provision. The 1972 Act, conferring precedence on EU law, was the sole example of that. However, Parliament still remained sovereign and had power to repeal the Act. The extent of its powers under the royal prerogative was delineated by UK constitutional law. An important aspect of Parliamentary sovereignty was that primary legislation was not subject to displacement by the Crown through the exercise of its prerogative powers. However, the constitutional limits on those powers were more extensive. The Crown only had powers recognised by the common law, and their exercise only produced legal effects within boundaries so recognised. That subordination of the Crown to law was the foundation of the rule of law in the UK, Case of Proclamations 77 E.R. 1352 and Zamora, The (No.1)  2 A.C. 77 followed. The conduct of international relations and the making and unmaking of treaties on behalf of the UK were generally regarded as matters for the Crown in the exercise of its prerogative powers. By making and unmaking treaties, the Crown created legal effects in international law, but it did not, and could not, change domestic law. It could not, without Parliamentary intervention, confer rights on individuals or deprive them of their rights, JH Rayner (Mincing Lane) Ltd v Department of Trade and Industry  2 A.C. 418 followed (see paras 18-33 of judgment).
(2) The clear and necessary implication from the provisions of the 1972 Act was that Parliament intended EU rights to have effect in domestic law, and that that effect should not be capable of being undone or overridden by the Crown in the exercise of its prerogative powers. The secretary of state's contention that Parliament did not intend to abrogate the Crown's prerogative powers was rejected, R. v Secretary of State for Foreign and Commonwealth Affairs Ex p. Lord Rees-Mogg  Q.B. 552 considered. Parliament also intended that British citizens should have the category (ii) rights under the Act and EU law, namely those rights enjoyed by British citizens and companies in relation to their activities in other Member States, including freedom of movement, and that those rights should not be capable of being undone by the Crown's prerogative powers. The Act could not be regarded as silent on the question of what happened to those rights if the Crown sought to take action to undo them. The Act either reserved power to the Crown to undo them, including by giving notice under art.50, or it did not. It clearly did not. In the absence of such authority, the Crown could not exercise its prerogative powers to alter UK domestic law and modify rights acquired under the Act, or the other legal effects of the Act. The secretary of state did not, therefore, have power under the Crown's prerogative to give notice pursuant to art.50 for the UK to withdraw from the EU, De Keyser's Royal Hotel Ltd, Re  A.C. 508, R. v Secretary of State for the Home Department Ex p. Fire Brigades Union  2 A.C. 513 and Laker Airways Ltd v Department of Trade  Q.B. 643 followed (paras 57-66, 77-101).
(3) The secretary of state rightly did not contend that the 2015 Act supplied a statutory power to the Crown to give notice under art.50. The Act fell to be interpreted in the light of the basic constitutional principles of Parliamentary sovereignty and representative Parliamentary democracy applicable in the UK. A referendum could only be advisory for the Parliamentary lawmakers unless very clear language to the contrary was used in the legislation in question. No such language was used in the 2015 Act. The instant judgment did not question the importance of the referendum as a political event, the significance of which would have to be assessed elsewhere (paras 105-108).