R (MILLER) V SECRETARY OF STATE FOR EXITING THE EUROPEAN UNION
In this briefing,Tom Leary considers the Divisional Court's recent Brexit judgment on the government's power to give notice under Article 50 of the TEU for the United Kingdom to cease membership of the EU.
The prerogative powers
The prerogative powers are the residual common law powers of the Crown which have not been removed or curtailed by Parliament or the courts. They are, as Lord Reid said in Burmah Oil  AC 75 at 101, “a relic of a past age, not lost by disuse, but only available for a case not covered by statute”.
They are nevertheless a powerful and efficient relic, routinely used in the making and unmaking of international treaties.
Usually, such exercises of the prerogative only have a legal effect at the international level and do not alter domestic law. However, exiting the EU is a different story because EU law takes effect as a matter of domestic law by virtue of the ECA 1972.
The sole question for the Division Court to decide in this case was whether the government had the prerogative power to given notice under Article 50 of the TEU for the United Kingdom to cease membership of the EU without Parliamentary decision.
It was common ground between the parties that a notice of withdrawal under Article 50(2) would irrevocably and inevitably lead to the UK’s withdrawal from the EU.
Further, the Secretary of State conceded that the exercise of the prerogative would cause a loss of certain domestic rights, including the right to vote in elections to the European Parliament or seek a reference to the CJEU.
The claimants’ primary submission was that (i) it is a fundamental principle of UK constitutional law that the prerogative powers cannot be used to diminish or abrogate domestic legal rights; (ii) nothing in the ECA 1972 expressly or necessarily confers such a power on the government; and (iii) giving notice under Article 50(2) would inevitably abrogate the domestic rights flowing from the ECA 1972.
The claimants also had a secondary argument that, even if they were wrong to argue that the prerogative powers cannot be used to diminish or abrogate domestic legal rights, the effect of the ECA 1972 was to remove the prerogative power to give notice under Article 50(2).
The Secretary of State, in reply, submitted that (i) the prerogative power enables the government to unmake treaties; and (ii) nothing in the ECA 1972 expressly or necessarily abrogated that power.
What did the Divisional Court decide?
The Divisional Court accepted both the primary and the secondary arguments of the claimants and held that the government did not have the prerogative power to give notice of withdrawal under Article 50(2)
Five points were central to the Court's reasoning:
(1) It is a strong constitutional principle that the Crown should not have the power to vary the law of the land by the exercise of its prerogative powers.
(2) An exercise of prerogative power to give notice of withdrawal under Article 50(2) would not operate only on the international plane but would inevitably cause considerable changes in domestic law.
(3) It is to be presumed that Parliament intended to legislate in conformity with strong constitutional principles.
(4) Parliament clearly intended by the ECA 1972 to introduce EU law into domestic law in such a way that this could not be undone by the exercise of prerogative power, based on the wording of the statute itself and its overall constitutional purpose.
(5) Alternatively, in any event, the prerogative powers cannot be used to change or nullify rights under domestic law unless Parliament confers on the government the power to do so and the ECA 1972 contained no such authority.
Why does it matter?
In addition to its obvious and controversial political impact of the judgment (not to mention some fairly abhorrent criticism of the judiciary), this decision matters for two important reasons of constitutional law.
First, what effect (if any) can the exercise of prerogative power have on domestic law?
Despite the clear message from the Divisional Court that the prerogative power cannot be used to change or abrogate domestic legal rights, uncertainty remains over the scope of that constitutional principle. It is obvious that the prerogative power cannot be used to repeal or amend an Act of Parliament (that would be contrary to Parliamentary sovereignty itself) but what about an indirect impact on the effect of an Act of Parliament? The Court of Appeal in Post Office v Estuary Radio Ltd  QB 740 recognised that the prerogative power could be used at the international level even when the effect would be to expand the territorial application of a statute. Is this really consistent with the Divisional Court’s approach?
Further, the House of Lords in R v Lyons  UKHL 447 accepted that there is a strong presumption in domestic law that English law is to be interpreted in conformity with international obligations. So entry into international treaties can have at least indirect consequences for domestic law. Could it not be said that, in a similar way, a notice of withdrawal under Article 50(2) has only indirect domestic consequences for how the courts apply the provisions of the ECA 1972 and therefore does not amount to a prohibited change or abrogation of domestic legal rights?
The answer is likely to turn on whether, as Mark Elliot and Hayley J Hooper have written in their excellent article (https://publiclawforeveryone. com/2016/11/04/the-highcourts-judgment-in-miller-a-briefcomment/), the ECA 1972 is to be viewed “as a conduit for the effect in domestic law of rights that are EU law rights” or “as the creator of domestic rights” in itself.
Secondly, how should the ECA 1972 and Parliamentary intention be interpreted?
The Divisional Court found a "clear" Parliamentary intention to introduce EU law into domestic law in such a way that this could not be undone by the exercise of prerogative power, but is that really so clear?
The Supreme Court will now have to grapple with the proper interpretation of section 2(1) of the ECA 1972, which gives effect to rights, powers and liabilities "from time to time provided for by or under the Treaties". Does that prevent executive withdrawal from the treaties or does it simply make these domestic rights contingent upon, and subject to, the prerogative power as it is exercised at the international level? Is the Divisional Court's preference for the former view really consistent with the approach taken by the Court of Appeal in Post Office v Estuary Radio Ltd  QB 740 to similar wording in section 6 of the Wireless Telegraphy Act 1949?
What will happen in the Supreme Court?
The legal arguments are finely balanced and the outcome is likely to turn more on constitutional theory than black letter law. A unanimous judgment would be surprising and the case could go either way.
Hopefully, whatever the outcome, the Supreme Court will lay down definitive guidance on the scope of the prerogative power to make and unmake international treaties. And Nigel will decide to stay at home.
The Divisional Court accepted both the primary and the secondary arguments of the claimants and held that the government did not have the prerogative power to give notice of withdrawal under Article 50(2).
The arguments are finely balanced but the Supreme Court now has the opportunity to give definitive guidance on the scope of the prerogative power to make and unmake international treaties.