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

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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