Why the Article 50 case may be the most important constitutional case for a generation

13th October 2016

Today at the High Court in London the hearing begins of the challenge to the government about whether it can trigger Article 50 instead of Parliament.

The case is not about whether Article 50 is triggered or not.  The case is instead about who makes the decision.  Is the decision to be made by the government or by Parliament?

As a matter of law, the answer is not clear.

There are outstanding lawyers who in good faith disagree.

Because there is no exact precedent, the arguments on both sides draw on first principles.

Nobody can predict with certainty which way the court will go.

And whichever way the court goes, there will (no doubt) be a “leap-frog” appeal to the Supreme Court, where the case will probably be joined to the similar Northern Irish case (which also covers the Good Friday Agreement).  I understand the Scottish government may also intervene at the appeal stage.

The Supreme Court hearing may take place as early as December, and so this may be over by Christmas.  We may know before the end of the year whether, as a matter of domestic law, it is for the government or Parliament to decide.


My view is that the case may well be the most important constitutional case for a generation.

What is meant by a constitutional case? For me, it means a case which deals with relationships between the various parts of  a polity: the executive, the legislature, the judiciary, devolved and local governments, and (of course) citizens.

The constitution of any state is the description given in answer to the question: “how is this state constituted?”

This answer may focus on a single codified document called a “constitution”, or on any various legal documents (Acts of Parliament, leading cases, authoritative books) and conventions, as with the United Kingdom.

(The UK does not have an “unwritten” constitution, it is just not written down in one place.)

An “important” constitutional case is one which deals with relationships between state organs (and between state organs and citizens) where (a) the relationships are not clear and (b) the issue at stake is significant and needs resolving.

In the Article 50 litigation, these constitutional issues are:

– the scope of the “Royal Prerogative” ( a legal fiction which means the government can do important things in the name of the Queen which have legal effects without any statutory basis) as opposed to the scope of “Parliamentary sovereignty”;

– the relationship of both to the result of a national referendum (which is not legally binding but cannot politically be denied);

– the role of the courts in adjudicating tensions between the above;

– the extent to which an executive act can lead to individuals losing rights they otherwise would have under UK and/or EU law; and

– how all of this balances with the rights and interests of the devolved governments.

The government maintain that it has a general power to make and break international treaties under the Royal Prerogative (and/or a general power to invoke Article 50 as an executive action), and to the extent a mandate is needed, that is provided by the referendum result.

The challengers insist that any such decision is so momentous that it has to be done by Parliament, not least because of the way Article 50 could lead to individuals losing rights they otherwise would have.

My view, for what it is worth, is that in normative terms, it should be Parliament that makes the decision.

I believe plebicites and prerogatives to be illiberal devices, and I prefer representative democracy.

But this is a “should” not an “is”.

In positive terms, I do not know how this challenge will be decided.  I initially was on the side of it being a Prerogative act (and I did a thought-experiment along those lines here), but the potential impact on individual rights seems to be a powerful counter-argument.


There are not many important constitutional cases.  One sign of a stable polity is that they are few in number, as the relationships between parts of the state (and between the state and the citizen) are settled.

Cases of similar importance which come to mind are Factortame I (1990, on the courts vs Acts of Parliament under EU law) and M v Home Office (1994, on the executive vs the courts).  Other lawyers and legal commentators will suggest others.

In my view, the case starting today has the potential to match such cases in importance.


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20 thoughts on “Why the Article 50 case may be the most important constitutional case for a generation”

  1. Surely the Royal Perogative is much more than a legal fiction. I always understood it to be a constitutional convention whereby the Executive exercised the powers of the monarch.

    1. Given the Queen is not (directly or even indirectly) involved and the “on her behalf” is not (literally) true: what is the difference?

  2. This debacle needs dozens of hours of parliamentary scrubbing & scrutiny. For an up-front “non-binding” vote to suddenly be taken as 100% “the country voted it’s rights away” is disenfranchisement of the entire population, who most certainly didn’t vote on this unasked question!

  3. What do you mean by saying the Royal prerogative is a “legal fiction”? Normally that term is used for a status not held in practice but deemed to exist in law (the most well-known example being corporate personality). It seems odd to use this for executive power, which both legally and very practically exists.

  4. The attempt by the government to keep the initial arguments before the court free from public scrutiny suggested that as the referendum act had passed, parliament had no further role in the matter as it was “clearly surrendering its role” must be specious since the act is not binding on government. Equally, it suggests that promises by Mrs May to “thoroughly consult ” with devolved parliaments are quite hollow. A further point which seems to have been lost in the shuffle is that expatriots were denied a vote entirely (not just those of us working or living abroad for more than 15 years) which probably breaches EU human rights legislation still in force in these islands.

    1. As an expat myself, the voting arrangements for non-residents upset me enormously. However, the Outcome of the Schindler case probably means, regrettably, that arrangements are legal within the framework of the EU law/ECHR. I found the reasoning in the Schindler case hinged on the relative ease of an expat becoming resident. I re-registered as resident for a 2 week period to retain my voting rights (ref the 15 year rule) and has the electoral comission confirm my actions complied with the legal requirements. I would be more than happy to hear any arguments which go beyond the Schindler case and, in particular, any arguments about whether loss of rights stemming from the referendum outcome / decision to withdraw can be challenged in the European courts.

  5. As a non-UK citizen, I find it remarkable that after centuries of democracy the United Kingdom has not codified its constitution. It appears that because this was not traditionally done, that it is forever locked in a time warp dating back to 1264 or 1295. Surely, after more than seven hundred years, it is time to move on, if for no other reason than citizens would at least know their rights and the rights and responsibilities of their institutions of government? What exists in the UK today is a total lack of transparency for most normal citizens and something for only the most learned to debate. The fact that an appeal is deemed a foregone conclusion speaks volumes.
    While one may point fingers at many things in South Africa, we at least have a good constitution, and which is well exercised by the citizens of the country to keep its various spheres of government in check.

    1. Whilst it may seem odd at first glance, I think you attach too much importance to the form of a constitution as opposed to the constitutional reality. Zimbabwe, Belarus and North Korea all have codified constitutions but no-one would suggest that, in practice, this ensures good government and the ability of the citizen to hold the executive to account. Whilst ours is not codified, I would challenge your assertion that individuals in the UK do not know their rights (many are in statute, the Human Rights Act) or that we are unable to hold the executive to account (our courts regularly hear cases of judicial review against government actions).

      The point that the appeal is a foregone conclusion says nothing about the quality of our constitution, only that this case is of such constitutional significance that whatever side loses, they will appeal and so it will inevitably go to the Supreme Court. This is equally true of significant cases raised in the USA (a country which had one of the first written constitutions) which commentators know will inevitably have to be decided by the Supreme Court there.

      The one point where I would agree with you is that there is insufficient awareness amongst the public of our constitution, but this is addressed through better education and commentary. I don’t think this is an issue unique to the UK though. How many South Africans, for example, have actually read in full the constitution of South Africa and could tell you off the top of their head what rights and responsibilities it contains? Or would they have to look it up online first, in which case the situation is not that dissimilar from the UK.

      1. I hear your points, but still fail to understand the reluctance to codify the UK constitution. Is it really all about tradition?

        Yes, you are probably correct that many, if not most, South Africans do not know their constitution section by section or even the Bill of Rights within it. I however, doubt that they are alone. They do however know it is there and may turn to it when necessary.

        The lack of a truly independent and fearless judiciary I would suggest define the difference in your examples as compared to some other states. Zimbabwe did have fearless judiciary, but they were replaced. Their new constitution seems to offer hope with some judges now having taken politically challenging decisions. While perhaps one may think there is no need for similar concern in a democratic country such as the USA, this seems to be an ongoing issue from presidential election to election that future political appointments to their Supreme Court may swing the their balance of power.

  6. Many thanks for such a clear, lucid and succinct explanation of today’s court case. I shall be following outcomes with interest.

  7. I had thought that Parliament had long since established that it had the power to define, limit, or constrain the prerogative powers of the Monarch and her executive branch of government. With respect to the EU treaties, the Crown has already conceded that it general Royal prerogative to “make or break” treaties as acts of state is subject to the overriding authority of Parliament. Each of the EU treaties , including the Lisbon Treaty with its Article 50, has only become effective upon and been implemented by an express act of Parliament. In several of those enactments, Parliament has made express provision that there is to be no change or amendment to provisions of the treaty without the prior express authorization of a further act of Parliament. Each one of these acts has been accepted and enacted by Her Majesty.

    For the executive arm of government by a Cabinet or Privy Council decision to purport to issue a notification under Article 50 is to take an irrevocable (without the unanimous consent of 27 other nation states) step leading to the termination of all of the EU treaties 24 months later. That would seem to amend provisions of some of those treaties by terminating them. That is an executive act that Parliament has prohibited without its express authorization.

    Can the Crown now assert a wider interpretation of its prerogative powers and the executive powers of the Privy Council that would override or bypass the prior acts of Parliament? Indeed, this is a fundamental constitutional question. In Canada, we believe that, subject only to our individual rights under the Charter of Rights and Freedoms, Parliament is supreme.

  8. Agree with others about the clarity and conciseness of your explanations and your opinion that this is the most important constitutional law case for a generation. Rightly so. it is a case that needed to be brought; regrettably, my view is that many of those voting to leave thought that disengaging from the EU would be as legally simple as terminating membership of their local gym..At 70 years of age I have developed an interest in and passion for Constitutional Law that was sadly absent in 1965/66 when I was a youthful law degree undergrad…

  9. Interesting post.

    I think its an extraordinarily important constitutional case in the sense that the real world consequences could be enormous – but I’m not convinced its a particularly constitutionally important case – in the sense that the our understanding of the constitution probably won’t need re-assessment after the decision (contra cases in our lifetimes such as Factortame, Jackson, Thoburn and maybe even the under-appreciated Horncastle)

  10. Immediately post-Brexit, I clung to the possibility that it would require an act of Parliament to invoke article 50 but I’ve now moved on to an impatience to get it over with. Rather than focus on the constitutional aspect of Royal Prerogative, interesting as it is from a legal point of view, is there a constitutional aspect of law that, when EU law is repealed and adopted into UK Legislation (as the PM suggests) prevents repeal of these laws by anything OTHER than an act of Parliament? For my part, I would rather see the process begin as soon as possible now that I’ve recovered from the shock of it all, but with the certainty that important issues such as Free Movement cannot be summarily dismissed by the government without an act of Parliament. I keep hoping that someone, somewhere will reassure me that really, the only reason to be out of the EU is one of currency and its requirement to dictate common policies amongst members of the common currency. Why is there a reluctance to consider stepping out from the EU because it makes sense in this context, and remaining a member of the EEA and the EFTA? The Referendum dictates only the withdrawal from the EU. It does not require any other change of legislation or control of borders. And I apologise for my digression, but I want to believe so badly that this is a relevant argument and that the government can not be allowed to assume that a vote to leave the EU equates to a vote to restrict the movement of workers. To the latter, many of us are fundamentally, morally, ethically opposed. After all, we are all nothing more than an accident of birth.

  11. This is a very interesting post and thought provoking replies. But whoever does the deed, the fallout is the work thereafter required to develop GB as a foremost nation capable of handling her own affairs and foreign affairs competently. No mean task.

  12. While clearly an important and interesting case, it seems to me that there would be a much better (and cheaper) way to resolve it. Parliament is sovereign and, if it wanted to, could pass a law tomorrow (or certainly before March 2017) removing the prerogative power to trigger Article 50 (if such power exists). This case is surely just addressing an ambiguity about whether Parliament has already done that (perhaps implicitly, by granting certain rights to citizens). Shouldn’t Parliament answer that question itself, rather than sitting back while the Supreme Court does so? Or perhaps, by not passing such a law (or even a resolution objecting to the use of prerogative), Parliament can be taken to have already given its answer – after all, Parliament has been given plenty of notice.

    1. Simon, the mischief Parliament was intending to address by passing the 2015 Act that provided for the referendum was precisely to avoid Parliament taking a decision.

      Government proposers of the Bill clearly stated the purpose of the Bill was to provide for the UK’s “decision” to leave the EU in the referendum outcome.

      Interpretation of Acts of Parliament is an exclusive jurisdiction of the Courts. Parliamnet has no interpretative role after Royal Assent.

      The Courts can (I say must) construe the 2015 Act as the UK’s statutory decision for the purposes of Article 50(1) on the authority of the well-known case of Pepper v Hart [1993] AC 593


      Some of the evidence needed to do this – clear statements from Government proposers in Hansard prior to Royal Assent – is before the Court in the skeleton argument of the Secretary of State.

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