My Lords and my Lady, my clients are a group of ordinary British citizens and one Gibraltarian citizen who are all people who will be affected in a very significant way, in very significant aspects of their lives, by a decision to leave the EU and the profound changes this decision will make to the law of the United Kingdom and to their rights as European citizens. They have been crowd-funded by many thousands of relatively small donations from private individuals.
The issues in this case concern a long-standing constitutional principle, or long-standing constitutional principles. To some the legal arguments in the case may sound dry and antiquarian, and it is true that some of the principles that I rely upon have a long history, but that is not to diminish their importance. As Mr Eadie said, and I agree with him, the fact that a principle is well established does not make it an irrelevant anachronism today. Such principles can have a real and continuing value in contributing to the effective allocation of powers between the limbs of the state and in ensuring that they do not illegitimately intrude on to one another's territory.
On that subject, may I say one word on the role of the judges which has been the subject of intense interest in this case. The applications for judicial review before this court are not, of course, an attempt to persuade judges to usurp the power of any other arm of the state in an illegitimate way. They are certainly not, as Mr Eadie suggested in his closing observations on Tuesday morning, an attempt to persuade this court to undertake an act of judicial legislation.
The court is not being asked to decide whether in the light of the result of the referendum, the United Kingdom should leave or should not leave the European Union. Nor is it being asked to compel either the Government or Parliament to do anything. All the court is being asked to do is to consider whether as a matter of law, an intended act by the appellant to notify the European Union of a decision to leave on behalf of the United Kingdom would be a lawful act in the absence of express statutory authority. The relief which the respondents seek is for the court to uphold the declaration that the divisional court gave that he does not have such power and so it would be unlawful.
This is an entirely orthodox application for judicial review in that respect, even if it is not and I can't submit that it is, an entirely ordinary one.
So if I could outline our approach. Mr Eadie invites this court to find that the court can trigger Article 50 in exercise of the royal prerogative, even though this will alter domestic law, because it has what he described on Monday, and it is in the transcript at page 75, as an "untrammelled" prerogative power to do it.
We disagree with that. We reject the false assumption that the foreign relations prerogative extends to permitting the Government to dispense with domestic law and in his written case, paragraph 64, that is MS 12356, the appellant invites you to start your analysis at what we say is the wrong point by asking you simply to assume that there is a prerogative power to change the law, and then, basing yourselves on that assumption, to ask whether this presumed prerogative has been abrogated.
This is an artificial starting point. It is the wrong starting point, and the reason it is the wrong starting point is because it is almost halfway down the analytical track. But it is perhaps a convenient starting point for the appellant, because it bypasses what we say is the biggest hurdle which he faces in this appeal.
As Lord Sumption put it in questions to Mr Eadie on Monday and as Mr Gordon has submitted and as we put in paragraph 7 of our printed case, MS 12482, before you ever get to any question of abrogation, you have to ask a prior question. What are the limits, if any, of the prerogative power to make and unmake treaties? Does the treaty prerogative extend to changing the law on the national plane? Because if it doesn't, then no question of abrogation ever arises. We invite the court to approach this case from what we say is the true starting point by considering two questions.
The first question to address is as to the extent of the treaty prerogative and whether it extends to allowing the Government to effectively dispense with domestic law at all. We say it doesn't and that is my first proposition.
We say it is a fundamental constitutional maxim, not a mere generality, that the King, or, in this case, the appellant exercising the Crown's powers, may not, using the language of The Case of Proclamations, by his proclamation or any other way change the law or remove rights.
We say that the Bill of Rights and indeed the Claim of Right in Scotland and the Acts of Union put it beyond doubt that only the United Kingdom Parliament can change the law.
The second question to consider is whether triggering Article 50 would in fact change domestic law and remove European Union law rights which are recognised by it, contrary to the prohibition on dispensing with law, and we say that it would. That is my second proposition.
We say that European Union law is domestic law, and that rights conferred under it are domestic law rights, and that they are not contingent on an exercise of prerogative power. I will submit that Professor Finnis upon whose views the Government relies so heavily is wrong to say that section 2(1) of the European Communities Act is no more than a vessel, so that the existence of any domestic law rights is contingent on the exercise of a Government minister's entirely untrammelled general power to remove the very source of them.
That will be my second strand of submissions.
Finally, I will address you briefly on two short matters that have arisen during the course of oral argument.
Turning then to my first proposition, can I establish at once that we do not, of course, deny that subject now to the provisions of CRAG, the appellant has a power to enter, and -- not subject to the provisions of CRAG, to withdraw from international obligations on behalf of the United Kingdom. The court is not faced with a dispute about the existence of a treaty-making prerogative, nor indeed a dispute as to its exercise. This is not a misuse case. The only dispute as far as we see it is as to the extent of the prerogative which exists. The appellant puts the extent of the foreign affairs prerogative in issue, and Mr Eadie said on Monday that the prerogative power in the field of making treaties, ratification of treaties and withdrawal from treaties is and always has been, he said, always has been, a general power untrammelled by any implication that it cannot be used to change domestic law.
We say there is no prerogative power to change or dispense with the law as it stands outside the prerogative, whether that pre-existing law is contained in the common law or in acts of Parliament. So in that sense it goes beyond the issue of parliamentary sovereignty which Mr Chambers raised. My authority for that, I don't ask you to turn it up, is Lord Hoffmann in Bancoult (No 2), which is core authorities volume 4, tab 54, MS 2225, paragraph 44.
So faced with that dispute between the appellant and the respondents, the correct approach for the court to take, we say, is the one which was identified by Lord Bingham in Bancoult (No 2), and may I ask you to turn that up please --