John Adenitire: Exiting the EU Constitutionally

John AdenitireIn Miller v Secretary of State [2016], the High Court held that the Government cannot use its prerogative power to initiate the withdrawal of the UK from the EU.  In doing so, the High Court rejected every single argument that the Government put to it asserting the existence of the prerogative power.  The main reason for the outcome was that the exercise of the prerogative would abrogate statutory EU rights without the constitutionally required Parliamentary authorisation.  The Court found that proper construction of the European Communities Act (‘ECA’), which gives domestic effect to EU rights, in light of the sound constitutional principles barred the exercise of the royal prerogative.  This post analyses the Court’s reasoning by teasing out the relevant constitutional principles.  The post concludes by pointing out a constitutional worry, popular judicial legitimacy, which was not considered by the High Court.  This worry may induce the Supreme Court in a probable appeal to take a different approach.

Identifying Conflicting Constitutional Principles

The sole question that the Court was asked to address was whether it was legal under the UK constitution for the royal prerogative to be used to give notice under Art 50 TEU of the UK’s intention to cease to be a member of the EU ([4]).   Answering that question required identifying the relevant constitutional principles, some of which militated in favour of the claimants while others militated in favour of the Government.

The primary constitutional principle in favour of the claimants was that Parliament is sovereign and that ‘an important aspect’ of this principle is that ‘primary legislation [in this case the ECA] is not subject to displacement by the Crown through the exercise of its prerogative powers’ ([25]).  Secondly, the Court found that ‘the Crown has no power to alter the law of the land, whether it be common law or contained in legislation’ ([25]).  The Court identified several authorities for this proposition, including The Case of Proclamations (1610) 12 Co. Rep. 74, the Bill of Rights 1688 and statement of the Privy Council in The Zamora [1916] 2 AC 77.  These constitutional principles seem to lend support to the claimants’ assertion that the prerogative cannot be used to displace all EU rights which have been given effect in domestic law via s 2(1) ECA.

It is important to note, however, that there are counter-veiling constitutional principles which may give weight to the Government’s assertion of the existence of the relevant prerogative power.  The first is that the UK is a democracy and that the decision to exit the EU was one dictated by the exercise of democratic choice by the electorate through the EU referendum.  The second is that under the UK constitution it is orthodox that ‘as a general rule applicable in the normal circumstances, the conduct of international relations and the making and unmaking of treaties on behalf of the United Kingdom are regarded as matters for the Crown in the exercise of its prerogative powers’ ([30]).

Resolving the Conflict of Constitutional Principles

How did the High Court resolve the conflict between these grand constitutional principles? Mainly by showing that the principles which favoured the Government’s case were narrower than those that favoured the claimants.  First, even though the UK is indeed a democracy, the Court held that the UK is a ‘representative parliamentary democracy’ ([106]) and that, citing Dicey, ‘Judges know nothing about any will of the people except in so far as that will is expressed by an Act of Parliament’ ([22]).  The Court found that the European Union Referendum Act 2015 made the outcome of the EU referendum only advisory in law while being, arguably, a significant ‘political event’ ([108]).  It followed, on the Court’s view, that the outcome of the referendum could not strongly impact the outcome of the case.

The Court also circumscribed the relevance of the other constitutional principle which gives free rein to the Government in the international realm to make or unmake treaties.  For the Court that prerogative power ‘is regarded as wide and outside the purview of courts’ but only because, under normal circumstances, that power ‘does not and cannot change domestic law’ ([32]).  The Court followed here the proposition by Lord Oliver in Rayner [1990] 2 AC 418, who said, at [500], that

‘as a matter of the constitutional law of the United Kingdom, the Royal Prerogative, whilst it embraces the making of treaties, does not extend to altering the law or conferring rights upon individuals or depriving individuals of rights which they enjoy in domestic law without the intervention of Parliament’.

It was common ground, the Government having conceded, that some statutory EU rights would be lost as an effect of the notification under Art 50 ([63]).  Some of these rights included the ability for UK citizens to stand for election to the EU Parliament or to vote in such elections ([61]).  This concession was fatal to the Government’s case as it undermined the very constitutional purpose for which it had a wide prerogative power in international relations.  The Government could no longer back its case by reference to sound constitutional principles while the claimants’ constitutional case remained solid.

Interpreting the ECA Constitutionally

Lacking the backing of sound constitutional principles, the Government’s case was inevitably dismissed by the Court.  The contention that the ECA allowed the prerogative to alter the condition precedent of the domestic effect of EU rights, i.e. continued UK membership of the EU, was rejected as contrary to the text of that statute read in light of the constitutional principles which militated in favour of the claimants.  Paragraph 93 of the judgment was particularly telling in this regard.  In that paragraph, the longest in the judgment, the Court went through various passages of the ECA to identify that Parliament intended continued EU membership of the UK.  Telling examples were the long title of the Act which provided that it is ‘An Act to make provision in connection with the enlargement of the European Communities to include the United Kingdom’.  The heading of s 2 (‘General Implementation of Treaties’) indicated that the ‘Treaties’ explicitly set out in s 1(2) are to take effect in UK law.

The Government had argued that under s 2(1) ECA EU rights had domestic effect under EU treaties created or modified ‘from time to time’.  The ability of the prerogative to alter the content of those treaties, it was argued, was left unaffected by that section ([93(3)]).  This was the argument most defended in the academic community.  The Court explicitly rejected that argument as ‘flawed at a basic level’ ([85]) because it ‘had left out part of the constitutional background’, i.e. the constitutional principle that exercise of the prerogative power to make and unmake treaties could not alter, as the Government had conceded it would, the law of the land ([84]).

Conclusion: Has the High Court Left Out the Constitutional Principle of Judicial Legitimacy?

The Court’s reasoning should be applauded as a clear example of statutory interpretation deeply engaged with grand constitutional principles.  No doubt the Court’s reasoning will be subject to intense criticisms over the coming weeks and months.  Whether convinced or not by the Court’s own attempt, critics and supporters of the outcome of the case ought to follow the Court’s engagement with sound constitutional principles to make their own case.  It is in this fashion that the Supreme Court, if called to decide the matter, will probably approach it.

That leads to the question whether the High Court did not itself leave out a relevant part of the constitutional background when it quickly dismissed the outcome of the referendum as only a ‘political fact’.  For better or worse, the outcome of the case will be perceived as posing a stumbling block to what the majority of the electorate appeared to have decided when it voted for the UK to cease to be a member of the EU.  There are already tabloids and politicians calling for the heads of ‘undemocratic judges’ who want to stop Brexit.  No doubt some of these are inappropriate instances aimed at denigrating a thoroughly reasoned judgment which was the outcome of one of the most transparent proceedings in recent times (most of the crucial papers of the case and all the transcripts were publicly available).

Nevertheless, it is hard to argue that the idea of judicial legitimacy, a constituent part of the constitutional principle of judicial independence, does not itself partially rest on a political fact.  The relevant political fact might be of a different nature to that of the referendum: we do not elect judges.  Yet, judicial legitimacy does not only rely on the quality and transparency of judgments and proceedings.  It rests also and in part on the political fact of continued allegiance by institutions and the people to the fulfilment of the judicial duty to uphold the rule of law.  That allegiance may be threatened when judges are perceived, rightly or wrongly, to undermine the choice of the electorate.  It is not argued that losing some of that allegiance is not sometimes a necessary price to pay in the fulfilment of the judicial duty.  Nevertheless, in as much as that issue raises the constitutional problem of judicial legitimacy, it may inform the balance that the Supreme Court will decide to place on the other constitutional principles that guided the High Court in its interpretation of the ECA.  The Supreme Court may find that undermining the support and legitimacy it enjoys is too much of a price to pay for imposing Parliamentary supervision over Brexit.

John Adenitire, PhD Candidate in Law at Fitzwilliam College, Cambridge

(Suggested citation: J. Adenitire, ‘Exiting the EU Constitutionally’, U.K. Const. L. Blog (9th Nov 2016) (available at