The approach to the interpretation of the ECA 1972 as a constitutional statute – paras 82 to 85
At para 82 the court said - Statutory interpretation, particularly of a constitutional statute which the ECA 1972 is ... must proceed having regard to background constitutional principles which inform the inferences to be drawn as to what Parliament intended by legislating in the terms it did. This is part of the basic approach to be adopted by a court engaging in the process of statutory interpretation. Where background constitutional principles are strong, there is a presumption that Parliament intended to legislate in conformity with them and not to undermine them. One reads the text of the statute in the light of constitutional principle. In the particular context of the primary legislation which falls for interpretation, can it be inferred that a Parliament aware of such constitutional principle and respectful of it intended nonetheless to produce effects at variance with it?
Some examples are then given of that approach to statutory interpretation. Para 83 concluded by the court saying that - the stronger the constitutional principle the stronger the presumption that Parliament did not intend to override it and the stronger the material required, in terms of express language or clear necessary implication, before the inference can properly be drawn that in fact it did so intend. Similarly, the stronger the constitutional principle, the more readily can it be inferred that words used by Parliament were intended to carry a meaning which reflects the principle.
The court considered that the Secretary of State’s case left out part of the relevant constitutional background. This was the constitutional principle that, unless Parliament legislates to the contrary, the Crown should not have power to vary the law of the land by the exercise of its prerogative powers. The court considered the Secretary of State's submission to be flawed at this basic level and this view was reinforced by reference to two constitutional principles.
The principle that the Crown cannot use its prerogative powers to alter domestic law – paras 86-88
The first principle was that the Crown has no power to alter the law of the land by use of its prerogative powers. This was the product of an especially strong constitutional tradition in the United Kingdom and had evolved through the long struggle ... 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 [EU rights] 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 United Kingdom out of them.
The court then referred to the point that the ECA72 was regarded 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 took 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 was not plausible to suggest that Parliament intended to allow the Crown to be able by its own unilateral action under its prerogative powers to switch it off again – para 87.
The principle that Crown's prerogative power operates only on the international plane – paras 89 to 91
The second principle was the well settled limitation on the constitutional understanding that the conduct of international relations is a matter for the Crown in the exercise of its prerogative powers. The Secretary of State has overstated that constitutional understanding. It was precisely because the exercise of the Crown's prerogative powers in the conduct of international relations has no effect in domestic law that the courts accept that this is a field of action left to the Crown and recognise the strength of the understanding that it is not readily to be inferred that Parliament intended to interfere with it. But the justification for a presumption of non-interference with the Crown's prerogative in the conduct of international affairs is substantially undermined in a case such as this, where the Secretary of State is maintaining that he can through the exercise of the Crown's prerogative bring about major changes in domestic law.
Ex Parte Rees- Mogg
At this point (paras 90 and 91), the court considered the case of ex parte Rees-Mogg and said that the case did not offer guidance in the present case. This conclusion was reached by means of distinguishing the facts of Rees-Mogg from the facts in the present case. Nevertheless, since Rees-Mogg figures in the appeal, it is worth looking at it more closely.
The late Lord Rees-Mogg sought a declaration from the High Court that the UK government could not lawfully ratify the 1992 Maastricht Treaty on European Union. (The court accepted that Rees-Mogg acted because of his sincere concern for constitutional issues). The Treaty contained a Protocol on Social Policy – Protocol 14.
Three arguments put forward on behalf of Rees-Mogg failed in the High Court.
The first argument concerned section 6 of the European Parliamentary Elections Act 1978. This Act is of interest because, for the first time, the UK Parliament sought to impose restrictions on Ministers ratifying any EU Treaty which increased the power of the European Parliament.
It is argument number 2 that is of interest for present purposes. It was argued that Parliament had, by necessary implication, intended to curtail the prerogative power to amend or add to the Treaty of Rome. The court refused to accept this far reaching argument and said:
"We find ourselves unable to accept this far-reaching argument [for the claimant]. When Parliament wishes to fetter the Crown's treaty-making power in relation to Community law, it does so in express terms, such as one finds in section 6 of the Act of 1978. Indeed, as was pointed out, if the Crown's treaty-making power were impliedly excluded by section 2(1) of the Act of 1972, section 6 of the Act of 1978 would not have been necessary. There is in any event insufficient ground to hold that Parliament has by implication curtailed or fettered the Crown's prerogative to alter or add to the E.E.C. Treaty.”
The Miller and Dos Santos judgment at para 91 explains the court's reasoning for rejecting the submissions based on Rees-Mogg. It could not be read as holding that express words would be required to fetter the Crown's treaty-making power in relation to EU law, since the court looked to see if there was sufficient ground to hold that Parliament had by implication curtailed or fettered the Crown's prerogative in that regard.
That question arose in the context of the making of a Protocol to extend, not remove, EU rights. It is clear from the judgment that it was the fact that the ratification of the Protocol would not alter domestic law which led to the court's conclusion. The court did not have to consider an argument as to whether the Crown's prerogative powers had been unaffected by the ECA 1972. In the very different context of the present case, the question is whether the Crown has power under its prerogative to withdraw from the relevant EU Treaties where such withdrawal will, on the Secretary of State's argument, have a major effect on the content of domestic law. It is clear that the court in ex p. Rees Mogg did not touch on that question.
The 3rd argument put forward by Lord Rees-Mogg is not considered here.
(Note: Ex parte Rees-Mogg was raised in the appeal – Transcript Day 3 at pages 17-22).
Conclusion as to Parliament's intention – paras 92 and 93
The court concluded that it was clear that Parliament intended to legislate by the ECA 72 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 50 of the TEU.
That this was the intention of Parliament and the effect of the ECA72 appears from 8 provisions in the ECA read in the light of the relevant constitutional background. The 8 points are set out at para. 93. Then, at para 94, the court said that – “The clear and necessary implication from these provisions taken separately and cumulatively is that Parliament intended EU rights to have effect in domestic law and that this effect should not be capable of being undone or overridden by action taken by the Crown in exercise of its prerogative powers. We therefore reject the Secretary of State's submission that Parliament did not intend to abrogate the Crown's prerogative powers and had not done so through the ECA 1972.”
The claimant’s principal argument – paras. 95 and 96
The court had reached its conclusion by examining and rejecting the submission advanced by the Secretary of State. The court then turned to the claimants' principal contention that as a matter of general constitutional principle derived from the sovereignty of Parliament and the case law the contention of the Secretary of State was misconceived. It was their submission that the Crown could not change domestic law and nullify rights under the law unless Parliament had conferred upon the Crown authority to do so either expressly or by necessary implication by an Act of Parliament. The ECA 1972, in their submission, contained no such authority.
It followed from the detailed analysis of the court that the ECA 1972 conferred no such authority on the Crown, whether expressly or by necessary implication. Absent such authority from the ECA 1972 or the other statutes, the Crown cannot through the exercise of its prerogative powers alter the domestic law of the United Kingdom and modify rights acquired in domestic law under the ECA 1972 or the other legal effects of that Act. The court agreed with the claimants that, on this further basis, the Crown cannot give notice under Article 50(2).
Paras. 97 to 101 consider the cases of De Keyser, Fire Brigades Union and Laker Airways.
Paras. 102 - it was not necessary to address the supplementary submissions made by Miss Mountfield QC on the effect of the Act of Union of 1707.
Paras. 103-104 look at the Northern Ireland judgment of Maguire J in Re McCord's Application  NIQB 85. [See previous post on this case].
Paras. 105 to 108 look at the Referendum Act 2015 which did not (as accepted by the Secretary of State) give a statutory power for the Crown to give notice under Art 50.
The 2016 Act fell to be interpreted in light of the basic constitutional principles of Parliamentary sovereignty and representative parliamentary democracy which apply in the United Kingdom, which lead to the conclusion that a referendum on any topic can only be advisory for the lawmakers in Parliament unless very dear language to the contrary is used in the referendum legislation in question. No such language is used in the 2015 Referendum Act.
The 2015 Act was passed against a background including a clear briefing paper to parliamentarians explaining that the referendum would have advisory effect only. Moreover, Parliament must have appreciated that the referendum was intended only to be advisory as a Leave Vote would inevitably necessitate future decisions on many important questions relating to the legal implementation of withdrawal from the European Union.
The court concluded that the Secretary of State does not have power under the Crown's prerogative to give notice pursuant to Article 50 of the TEU for the United Kingdom to withdraw from the European Union.
In these posts, I have tried to present the judgment as it stands along with some background material in the various Notes. The judgment has not escaped critical analysis - see, for example Public Law for Everyone - Critical reflections on the High Court's judgment in R (Miller) v Secretary of State for Exiting the EU