Brexit: An Overlooked Analogy? Article 50 of the TEU & Section 25 of the CRAG Act 2010

We are delighted to welcome this guest post by Conor McCormick, PhD candidate, QUB School of Law. Conor can be reached on

Article 50 of the Treaty on European Union is quickly becoming the most limelit legal provision of the century. Prolific debate and high-profile litigation over the meaning of its reference to the ‘constitutional requirements’ of the UK, in the context of a decision to withdraw from the European Union, is proving to be very contentious indeed. In this short blog, I attempt to draw what I hope is an instructive analogy in support of the proposition that Parliament’s permission ought to be obtained before a notification in accordance with Article 50 is used to establish the UK’s intention to withdraw from the EU. I argue constitutional consistency demands that more attention be given to the object of my analogy.

The Constitutional Reform and Governance Act 2010 is the object of my analogy. It provides that Parliament’s permission must be obtained before an international treaty may be ratified. For details, consult Part 2 of the Act. I do not detail here the specific statutory requirements for parliamentary approval in respect of amendments or replacements to the TEU or TFEU, or for the ratification of other ancillary EU treaties. They are dealt with in the Miller judgment.

For present purposes, I think it is apposite that ‘ratification of a treaty’ is generally defined by s 25(3) of the 2010 Act as an act which ‘establishes as a matter of international law the United Kingdom’s consent to be bound by the treaty’. Acts of this kind are illustrated by the following two examples provided in s 25(4):

(a) deposit or delivery of an instrument of ratification, accession, approval or acceptance;

(b) deposit or delivery of a notification of completion of domestic procedures.

The example provided in s 25(4)(b) makes it abundantly clear that if a Minister of the Crown intends to establish the UK’s consent to be bound by an international law agreement having an effect upon domestic law and to make a notification to that effect, he or she must first obtain Parliament’s permission through the procedures set out elsewhere in Part 2 of the Act. Parliament’s permission, in this context and to this extent, characterises the requisite ‘domestic procedures’ needed to establish the existence of the UK’s consent as a nation state. In my view, there is a strong correlation between the meaning given to the expression ‘domestic procedures’ in this context and the phrase ‘constitutional requirements’ found in Article 50(1), not least because Article 50(2) has been identified as the primary route of establishing a withdrawal of consent to be bound by the EU treaties on the part of the UK.

It seems to me, by reverse analogy, that if a Minister of the Crown intends to establish the UK’s withdrawal of consent to be bound by international law agreements having an effect upon domestic law and to make a notification to that effect, Parliament’s permission is equally material to such a determination. To what extent, however, does this analogy really support the case in favour of mandatory parliamentary involvement in the decision to notify the European Council under Article 50(2)?

Well, the Constitutional Reform and Governance Act 2010 transposed a political convention in respect of treaty ratification known as ‘the Ponsonby Rule’ onto a statutory footing precisely because parliamentary scrutiny of binding international law agreements which require alterations to domestic law was deemed a matter of considerable importance. While the 2010 Act does not bite upon the notification procedure under Article 50 directly, I do think it adds further weight to the argument in favour of parliamentary involvement on the ground of constitutional consistency. Arguments attempting to distinguish ‘ratification’ from ‘notification’ in this context seem little more than semantic manoeuvring to me.

We are in unprecedented circumstances. If one is willing to accept that the 2010 Act gives clear effect to a matter of important constitutional principle, then one cannot reasonably argue that the mirror image of that principle should be discarded simply because it finds no specific basis in statute. The UK’s mixed model of legal and political constitutionalism must be capable of delivering greater consistency than that, especially in an area of such serious significance and at a time of such high urgency.