Yesterday the Attorney General made a statement about my legal opinion on the joint instrument and unilateral declaration concerning the withdrawal agreement. During the debate Sir William Cash made the following intervention:

The Attorney General (Mr Geoffrey Cox): With permission, Mr Speaker, I would like to make a statement about my legal opinion on the joint instrument and unilateral declaration concerning the withdrawal agreement published last night.

Last week, I confirmed I would publish my

“legal opinion on any document that is produced and negotiated with the Union.”—[Official Report, 7 March 2019; Vol. 655, c. 1112.]

That has now been laid before the House. This statement summarises the instruments and my opinion of their legal effect.

Last night in Strasbourg, the Prime Minister secured legally binding changes that strengthen and improve the withdrawal agreement and the political declaration. The Government laid three new documents reflecting those changes in the House: first, a joint legally binding instrument on the withdrawal agreement and the protocol on Northern Ireland; secondly, a unilateral declaration by the United Kingdom in relation to the operation of the Northern Ireland protocol; and thirdly, a joint statement to supplement the political declaration. The legal opinion I have provided to the House today focuses on the first two of those documents, which relate to the functioning of the backstop and the efforts of the parties that will be required to supersede it.

Let me say frankly what, in my opinion, these documents do not do. They are not about a situation where, despite the parties properly fulfilling the duties of good faith and best endeavours, they cannot reach an agreement on a future relationship. Such an event, in my opinion, is highly unlikely to occur, and it is in the interests of both the United Kingdom and the European Union to agree a future relationship as quickly as possible. Let me make it clear, however, that were such a situation to occur, the legal risk, as I set it out in my letter of 13 November, remains unchanged. The question for the House is whether in the light of these improvements, as a political judgment, it should now enter into those arrangements.

Let me move on to what the documents do achieve. As I set out in my opinion, the joint instrument puts the commitments in the letter from Presidents Tusk and Juncker of 14 January 2019 into a legally binding form, and provides, in addition, useful clarifications, amplifications of existing obligations, and some new obligations. The instrument confirms that the European Union cannot pursue an objective of trying to trap the UK in the backstop indefinitely. It makes explicit that that would constitute bad faith, which would be the basis of a formal dispute before an arbitration tribunal. That means, ultimately, that the protocol could be suspended if the European Union continued to breach its obligations.

The joint instrument also reflects the United Kingdom’s and the Union’s commitment to work to replace the backstop with alternative arrangements by December 2020, including as set out in the withdrawal agreement. Those commitments include establishing

“immediately following the ratification of the Withdrawal Agreement, a negotiating track for replacing the customs and regulatory alignment in goods elements of the protocol with alternative arrangements.”

If an agreement has not been concluded within one year of the UK’s withdrawal, efforts must be redoubled. [Laughter.]

(…)

In my view, as a matter of law, the provisions relating to the timing of the efforts to be made in resolving withdrawal agreements make time of the essence in the negotiation of a subsequent agreement. A doctrine with which the lawyers in the House will be familiar is of legal relevance. In my opinion, the provisions of the joint instrument extend beyond mere interpretation of the withdrawal agreement, and represent materially new legal obligations and commitments which enhance its existing terms.

Let me now turn to the unilateral declaration. It records the United Kingdom’s position that, if it were not possible to conclude a subsequent agreement to replace the protocol because of a breach by the Union of its duty of good faith, it would be entitled to take measures to disapply the provisions of the protocol in accordance with the withdrawal agreement’s dispute resolution procedures and article 20, to which I have referred. There is no doubt, in my view, that the clarifications and amplified obligations contained in the joint statement and the unilateral declaration provide a substantive and binding reinforcement of the legal rights available to the UK in the event that the Union were to fail in its duties of good faith and best endeavours.

I have in this statement, and in the letter that I have published today, set out, frankly and candidly, my view of the legal effect of the new instruments that the Government have agreed with the Union. However, the matters of law affecting withdrawal can only inform what is essentially a political decision that each of us must make. This is a question not of the lawfulness of the Government’s action but of the prudence, as a matter of policy and political judgment, of entering into an international agreement on the terms proposed.

Sir William Cash (Stone) (Con): I thank my right hon. and learned Friend for his opinion, which is not only for the Government, I would stress, but for Parliament and for the voters. The substance of the backstop issue to which he has just referred is the legal, constitutional and, therefore, political status of Northern Ireland within the United Kingdom, which cannot be put at risk.

My right hon. and learned Friend refers to a reduced risk of the UK being “indefinitely” detained in the protocol, but he adds that, ultimately, there is

“no internationally lawful means of exiting”

unless both the EU and the UK agree. Does he therefore appreciate, on his own terms, that this fundamental legal impediment trumps political considerations and that, therefore, there would be insufficient protection for Northern Ireland to continue as part of the United Kingdom?

The Attorney General: I do not agree. My hon. Friend knows we have a difference of opinion, and I hope that he will move towards my position. I still hope that might be so, and I say that because one has to look at the mutual incentives and disincentives for both parties to stay in the arrangement. I made this point in December and, for the reasons I advanced in December and in my November opinion, the incentives or disincentives for the European Union are as profound, if not greater, to get us out of the backstop than to keep us in it. That is what I firmly believe. He may disagree, but that is what I believe.

That is why I have taken the political judgment that this withdrawal agreement needs to be supported but, in saying that, these improvements do make a difference. In the last line of my advice, I say there can be no lawful exit unless there is a fundamental change of circumstance. It is extremely important to remember that there is always a right to terminate a treaty unilaterally if circumstances fundamentally change. There is no question but that we have a right to exit if those circumstances apply.