Backstop/Northern Ireland and Ireland Protocol

The main issue that could lead to Parliament rejecting the Withdrawal Agreement is the backstop which is referred to as the Northern Ireland and Ireland Protocol. In response to questions raised with me I asked the following question to the House of Commons Library. Please see below their independent analysis.


“Should the backstop measure within the proposed withdrawal agreement be needed, is the UK free under international law to withdraw itself regardless of the position of the EU?”


Please see below an extract from our soon to be published briefing paper on the Withdrawal Agreement, followed by a short analysis:


International Law- Vienna Convention

The review mechanism in the Irish Protocol has brought renewed attention to how international law governs agreeing to and exiting from treaties.

The main body of international law on treaties is contained in the 1969 Vienna Convention on the Law of Treaties .

The Convention sets out conditions (Articles 46-53 & 64) which render a treaty invalid, so that it no longer binds the parties to it. These relate to treaties concluded under duress or in error, and other similar conditions. None of these provisions would likely apply to the UK in respect of the Withdrawal Agreement.

The Convention includes provisions (Articles 42-45 & 54-64) on the termination and suspension of the operation of treaties.

The Convention also includes the established principle in international law: ‘pacta sunt servanda’, or ‘treaties should be observed’.

The international law rule pact sunt servanda means that agreements are binding on the parties to them and must be carried out in good faith. It does not mean that treaties cannot be terminated; but the grounds for doing so (contained in the Articles referenced above) are limited. They include:

·                Termination by treaty provision or consent: a treaty may be terminated or suspended in accordance with a specific provision in that treaty. Even if there is no such provision, it can be terminated if all the parties agree.

·                Intended or implied right to unilateral termination: despite the principle of pacta sunt servanda, a state can unilaterally terminate a treaty either if it can be shown that the parties intended to allow termination, or if the right to terminate can be implied by the nature of the treaty.

·                Where the purposes and object of the treaty have been fulfilled or it is clear from its provisions that it is limited in time and the required period has ended.

·                Material breach by the other state: where one state violates an important provision and the other state (for bilateral treaties) ‘retaliates’ by regarding the whole agreement as ended.

·                Supervening impossibility of performance: where the agreement cannot be carried out because of the ‘permanent disappearance or destruction of an object indispensable for the execution of the treaty’.

·                Fundamental change of circumstances: the doctrine of rebus sic stantibus provides that where there has been a fundamental change of circumstances since an agreement was concluded, a party to that agreement may unilaterally withdraw from or terminate it. This is narrowly interpreted: the existence of those circumstances must have constituted an essential basis of the consent of the parties to be bound by the treaty; the change must have been unforeseen by the parties; and the effect of the change must be to transform radically the extent of obligations still to be performed under the treaty.

Professor Dehousse, former Justice of the CJEU, was asked about the Protocol’s ‘exit clauses’ and international law, when giving evidence to the Exiting the EU select Committee:

First, there is an exit from this exit, but when you read the provisions of the Vienna Convention you will need to take in many elements of the field. I cannot answer you precisely because I need to know the context in the future. There will be other things surrounding. What will be the agreements in the states and the parties implicated in those? If you read the basic provisions of international law, you will know there are always ways to exit. The question now is in which circumstances and with which conditions, et cetera. It is a complex matter. I do not believe one can answer you yes or no now, most unfortunately, as with most of the problems in this negotiation, by the way.[1]



The Library cannot give legal advice, but I believe looking at these provisions, there aren’t any obvious flaws in the ‘exit clauses’ of the Irish Protocol, which would allow the UK it shouldn’t be bound by what it has agreed to in the treaty.

This is in part because the Withdrawal agreement would allow a dispute over the UK exiting the backstop to the Independent Arbitration Panel, which is also established by the Agreement.

The matter could be referred to the International Court of Justice, but for them to give a binding ruling both the EU and the UK would have to agree on referring the case.