Diego Garcia Military Base and British Indian Ocean Territory Bill

Lord Murray of Blidworth Excerpts

Committee stage
Tuesday 18th November 2025 Lords Chamber

[Lord Jay of Ewelme (CB)]

My Lords, after the history lesson from the noble Lord, Lord Hannan, I am tempted to recount my time in Malta in the 1950s or my visit to Djibouti in 1965, but I will resist that temptation—at least this evening.

As I said at Second Reading, I support this necessary and sensible Bill, but I want to pick up something that the noble Lord, Lord Grocott, said. I do not agree with the proposed Amendment 1 of the noble Lord, Lord Callanan, but, as I said at Second Reading, the Government need to give very serious thought to how the rights, interests and wishes of the Chagossians— I say Chagossians in the plural to mean not just those who have written to us from the United Kingdom but those from elsewhere as well—need to be taken very seriously into account by the Government. I look forward to hearing more about the Government’s intentions later in our discussion in Committee.

[Lord Murray of Blidworth (Con)]

My Lords, for fear of treading on the toes of my noble friend Lord Hannan, I want to add to the debate that took place a moment ago concerning the intervention by the noble Lord, Lord Purvis of Tweed, on my noble friend Lord Callanan’s amendment. I invite noble Lords to look at Clause 1. Clause 1(1) provides that the treaty is the treaty that was considered by Parliament. Clause 1(2) expressly provides that:

“When the Treaty comes into force, so do sections 2 to 4”


of the Bill.

The Bill is indivisibly connected to the implementation of the treaty, as the Minister will no doubt tell us in her closing speeches to all the groups that we have today. This is reflected in the Explanatory Notes to the Bill. I commend to the noble Lord, Lord Purvis of Tweed, paragraph 18 of the Explanatory Notes, which sets out in crystal-clear detail that:

“Entry into force of the Treaty is defined in Article 18 of the Treaty, as being the first day of the first month following the date of receipt of the later note”.


There is nothing in the fact that this Parliament has considered the treaty that precludes an amendment of the type advanced by my noble friend Lord Callanan, because it is a statement of the purpose of the Bill. Purpose clauses have become something of a norm in legislation, and there is nothing wrong in principle with such a statement being placed in the Bill. Indeed, the purpose of the second part of his amendment is simply to state, as a matter of fact:

“Nothing in this Act grants or recognises that Mauritius has sovereignty over the Chagos Archipelago”.


That statement is absolutely correct. I give way to the noble Lord.

[Lord Purvis of Tweed (LD)]

I am grateful to the noble Lord for giving way; I have listened carefully to what he has said, as I always do. Does he agree that there is a distinction, however, between debating legislation that gives effect to a treaty that has been agreed and ratified by Parliament, which this treaty has, and implementing legislation which seeks to alter a treaty that has been agreed?

[Lord Murray of Blidworth (Con)]

The noble Lord seeks to justify his intervention but fails to do so. Because of the way the treaty is drafted and the way Article 18 operates, the treaty can come into force only when this legislation is implemented. That is unusual, but it has the effect of not allowing the noble Lord to make the point he tries to make. He argues that my noble friend Lord Callanan cannot make this amendment because it is in some way in breach of the agreement that has already been signed by the Government, but that agreement is not in force. This is a point we have explored in great detail. I am sure the Minister would agree with me on that point.

Moving to the other amendments in the group, I entirely support the amendments in the name of my noble friend Lord Lilley. I am very grateful to the reference that he and my noble friend Lord Bellingham made to the points that I made at Second Reading in respect of the non-recognition of the International Tribunal for the Law of the Sea. I would just add one point in furtherance of that. The International Court of Justice also has no power and no jurisdiction to query the dispute over the Chagos.

The noble Lord, Lord Hannay, who I am sad to see is not in his place, heavily relies on the evidence of Sir Christopher Greenwood, but he chooses to ignore evidence which does not favour his case. A very powerful exposition of the contrary case was put by Professor Richard Ekins, KC, professor of constitutional law at Oxford. He made it clear that the International Court of Justice’s jurisdiction specifically excludes any dispute with the Government of any other country which is or has been a member of the Commonwealth. Mauritius’s acceptance of the ICJ’s jurisdiction also excludes disputes with the Government of any other country which is a member of the British Commonwealth of nations.

If there had been any basis upon which Mauritius could have sought a binding ICJ judgment against the UK, it would have already done so. The fact is that no such basis exists or has ever existed, which is why Mauritius was forced to use the advisory opinion route to obtain its non-binding advisory opinion. Its bargaining position would have been far stronger if it had had a binding ruling against the UK, but the fact is that it has chosen to negotiate without seeking such a ruling, because it obviously knows that there is no way in which it can obtain such a binding ruling.

For those reasons, I strongly support the lock that is present in my noble friend Lord Lilley’s amendment. It would mean that only if there is a binding ruling should this treaty come into force, and therefore the Chagos Islands should remain in British possession and this act of strategic self-harm should be avoided.

--- Later in debate ---

[Baroness Chapman of Darlington (Lab)]

I am speaking for myself; other noble Lords may take different views on that point.

Mauritius could also pursue a legally binding judgment through further arbitral proceedings against the UK under Annex VII of the UN Convention on the Law of the Sea, or UNCLOS. A judgment from such a tribunal would be legally binding on the UK—and I will come on to the points about the extent of those judgments and sovereignty, too. Such cases could be brought rapidly and include provisional measures, themselves legally binding, which could be introduced within weeks. The long-standing legal view of the United Kingdom is that the UK would not have a realistic prospect of successfully defending its legal position on sovereignty in such litigation.

The other important element to note here is that, even if the UK chose to disregard any legal rulings—that is not something that this Government would want to do, but we could—we rely on third countries to service the base. Therefore, the operability of the base depends on other states taking a view on such rulings. We of course control what we do, but we cannot control what other states do. If we need those states to agree with us and to ignore a legal ruling too, we may not be successful. It may be that we then compromise the operability of the base. That is a very real threat; we were concerned about that, as were our allies and partners, including the United States.

The risk of a binding ruling relating to sovereignty from this type of tribunal is simply too great, given the importance of the base for national security. Some have pointed to the 2015 arbitration between the UK and Mauritius, in which the tribunal was clear that it did not have jurisdiction over the question of sovereignty. That is right. However, that was before the advisory opinion in 2019 and before the 2021 judgment of a special chamber of the International Tribunal for the Law of the Sea in a case about delimitating the boundary between Mauritius and the Maldives. In that case, it was ruled that Mauritius’s sovereignty was inferred from the ICJ’s advisory determinations. These have changed the legal landscape.

[Lord Murray of Blidworth (Con)]

Will the Minister confirm that, in those proceedings to which she just referred, the United Kingdom was not a party and made no submissions?

[Baroness Chapman of Darlington (Lab)]

I never said that we did; that was between Mauritius and the Maldives. My point is to make the case to noble Lords that the advisory opinions—advisory though they are—stand to inform subsequent opinions of international tribunals. That is what happened in that case, and that is why I bring that as a supporting argument for the Government’s case—to help noble Lords understand how we have got to where we are.

While an arbitral tribunal under UNCLOS almost certainly would not address the question of sovereignty directly, it may reach decisions on related matters based on conclusions about sovereignty. Noble Lords may disagree, but the Government’s position is that we are concerned about this—and I suggest that the previous Government were also concerned about this; otherwise, what were they doing? We are concerned not just about the effects of a binding judgment on the UK but about the legal effect on third countries and international organisations, which could give rise to real impacts on the operation of the base and the delivery of all its national security functions.

Although I do not expect there to be agreement on this, I believe that we cannot say that the Government have not fully considered all the potential legal jeopardy in which we would place ourselves. Further, we believe that the suck-it-and-see approach that the noble Lord, Lord Lilley, advocates would leave us in a much weaker position when it comes to negotiating with Mauritius.