While the question of when the British government should trigger Article 50 to begin Brexit negotiations has become a national obsession, some are turning their attention to another matter – once invoked, can Article 50 be revoked?
The issue matters for a number of reasons. Most obviously, given that the Brexit process is likely to take an extended period of time, the situation – internally in the UK and among the remaining EU27, as well as externally in the wider world – might well change. It might become necessary to call for a break before the full Brexit process can be concluded.
The issue of revocation also has implications for the relative bargaining power of the various parties to Article 50. If there is scope for terminating matters, and for Britain to remain within the EU after triggering Article 50, this might alter the nature of the negotiations that take place.
Revocation could come in various forms. The most likely scenario would be for the EU27 and the UK to agree between them to halt Brexit negotiations. This is clearly unproblematic in political terms (albeit less so in a legal sense). While nowhere in Article 50 does it actually say revocation is possible, the member states are masters of the EU’s constituent treaties so they can make the necessary adjustments if they’re all in agreement.
It wouldn’t be possible for the EU27 to force the UK to turn back after starting negotiations because of both Article 50 and customary international law. Any member state has the right to leave the EU under the former, and cannot be bound to international commitments under duress under the latter.
The more complex situation would be if the UK decides to abort Article 50 without seeking the approval of the EU27. If this is possible, then it changes the balance of bargaining power. It offers a third option to a British government faced with a take-it-or-leave-it offer from the EU27 and a ticking clock to the end of the negotiating period.
Even in a relatively benign scenario, where the British government has had a change of heart, but has been unable to convince the EU27 to accept it, then the basic question remains whether it can make this decision by itself.
Unfortunately, the legal position on this is not clear. Article 50 itself makes no provision for this situation and the 1969 Vienna Convention on the Law of Treaties offers only limited guidance. The Convention works on the general concept that until one is not a member, one is a member.
The complications inherent in this, however, are various. First, not all EU member states are signatories to the Vienna Convention, so are not bound by it. The EU itself is not a signatory, so would have to decide whether it had to respect the rights of those member states that are signatories.
This leads to a second objection, namely that the Convention is intended for cases where no exit mechanism exists (something that is not the case for the EU treaties). Since Article 50 is an exit mechanism and requires the member state to have some internal decision-making process to get to notification, and since it does not insist on a deal being reached with the departing member state, then effectively that member state might be seen to have ceded its rights to change its mind.
The critical problem comes should the UK be felt to be making a vexatious use of unilateral revocation. The obvious case would be if the British government revoked Article 50 in the face of a bad deal, and then shortly afterwards submitted a new Article 50 notification, in the hope of securing a better deal from the EU27 with the clock reset. Such an approach would not only be highly politically damaging, but would open the door to the ejection of the UK for non-compliance with the treaties.
In summary, Article 50 can be revoked, certainly by mutual consent, and probably unilaterally by the UK. However, the latter case would be highly unusual and would come with a lot of legal and political problems far beyond the narrow point of law.
This article also appears on The UK in a Changing Europe