Diego Garcia Military Base and British Indian Ocean Territory Bill

Lord Hannay of Chiswick Excerpts

2nd reading
Tuesday 4th November 2025 Lords Chamber

[Lord Hannay of Chiswick (CB)]

My Lords, I have been advised that it is not obligatory for me to declare an interest in this matter but, on the basis that it is better to be safe than sorry, I will do so. During a period in 1979, I was the head of the Foreign and Commonwealth Office department responsible for the British Indian Ocean Territory.

The Bill to which we are giving a Second Reading—and I hope that is what we are doing—is by no means the first time the House has debated the UK-Mauritius treaty on the Chagos Islands. Ratification under the CRaG procedure took place on 30 June on the basis of a report from your Lordships’ International Agreements Committee, on which I have the honour to serve but not to represent. The House was divided by the Opposition on that occasion but the report was endorsed by a majority, and the CRaG process was thus completed in the sense recommended by the committee. Today’s Bill is simply needed to bring our domestic legislation into line with that decision. I hope that that can now be done speedily and without further controversy. It is with some regret that I hear signs that that may not happen.

The legal testimony the International Agreements Committee was given before it reached its conclusion that the agreement should be ratified was not unanimous, but the committee’s view was that the most compelling evidence was that of Sir Christopher Greenwood, a former British judge of the International Court of Justice. His view was that if the UK were not to ratify the agreement, Mauritius could be expected to pursue actively the matter through international courts and, in the light of the opinion handed down by the International Court of Justice, to win such cases with damaging consequences for our security interests in the base at Diego Garcia and for those of our closest security ally, the United States. In addition, Sir Christopher pointed out that it was not correct to assert that the UK agreement with Mauritius amounted to the seceding of sovereignty since the International Court of Justice opinion already established that that step had been taken when the UK granted independence to Mauritius. That view was accepted by the international community.

It is relevant too to recall that Governments of both main parties have frequently stood at the Dispatch Box and stated, without ambiguity, that the British Government upheld the rules-based international order. It cannot seriously be disputed that a finding of the International Court of Justice, whether advisory or mandatory, is an integral part of that rules-based order. To suggest now that the International Court of Justice opinion could be ignored or set aside would surely be incompatible with those statements of policy so frequently repeated. At a time when the rules-based order is under such widespread attack, that course could hardly be in our national interest. Nor can we afford to ignore the fact that the 99-year lease on the base at Diego Garcia, with the possibility of extension, is sufficient to meet the security requirements of our closest ally, the United States, which is backing the agreement. To put those interests at risk by frustrating their implementation would seem to be an act of singular folly.

All this is to ignore the fact—as has been made clear in the debate already—that the previous Government held 11 rounds of negotiations on a similar basis to what has now been concluded in a negotiated agreement. If last year’s election had had a different result, can it be seriously doubted that the present Opposition would have been defending an agreement similar to the one that this House cleared on 30 June? None of these considerations invalidates the judgment that successive British Governments behaved in a lamentable way towards the Chagossian inhabitants of the islands, many of whom are now British citizens. The provisions agreed to mitigate these past failings are part of the Bill before us today, and rightly so. They are not, however, a reason to reject the agreement, or to delay it. To do that would in reality bring no satisfaction or benefit to anyone—quite the contrary.

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[Baroness Goldie (Con)]

That is an unexpected source of encouragement, for which I thank the noble Lord.

Finally, and very importantly, the defence and security implications of this arrangement are clearly ringing alarm bells, as noted in the contributions from my noble friends Lord Lilley, Lord Blencathra, Lord De Mauley and Lord Bellingham. My noble friend Lord Bellingham helpfully distinguished between this agreement and the sovereign base areas in Cyprus, to which the noble Lord, Lord Beamish, referred. The whole point is that we have sovereignty in Cyprus and can control these arrangements, but we cannot under this arrangement: we are in the hands of the agreement and Mauritius’s disposition to us.

The Minister described the base as a prized military asset. I was very glad to hear that and, of course, I agree. It was also emphasised by the noble Lord, Lord Jay. But it is this aspect of defence and security to which I wish to devote my final remarks. The Minister already has a lot of questions to which a response is required, and the observations from my noble friend Lord Lilley certainly require comment, but here is my addendum.

With the help of the Bill, I have been endeavouring to knit together the components of the agreement with the text of the Bill. Seeking clarification from the Government on a number of vital points is part of a necessary scrutiny process, but His Majesty’s Opposition reserve their overall position on the Bill and will determine their approach at a subsequent stage in the procedure. In the meantime, let me set a general perspective.

We reach the ninth introductory paragraph to the agreement before there is any mention of

“protecting international peace and security”,

with specific reference to

“the long-term, secure and effective operation of the Base on Diego Garcia”.

Although I might have hoped for earlier recognition of the primacy of defence and security, this is where we are. But the drafting confirms that this is a pivotal part of the agreement, which then promotes defence and security to Article 3 of the agreement and enhances that status by including Annex 1, so progress has been made. I mention this because it goes to the heart of what the agreement stands for, what it is about, and the need for absolute clarity.

There is the further question of the extent to which material text in the agreement should be replicated in the Bill. I propose to raise a number of factual questions, which I appreciate may require the Minister to go back to her officials. I am content that she does that and can respond by letter, a copy of which could perhaps be laid in the Library. At least the Government have now helpfully provided some time within which to do that.

Going back to the agreement, under Article 3,

“the Parties shall not undermine, prejudice or otherwise interfere with the long-term, secure and effective operation of the Base, and shall cooperate to that end”.

That is an undertaking of fundamental importance by Mauritius to the UK. It explicitly implies that Mauritius should not enter into any arrangements, either on its own account or with any third party, which could be in breach of that undertaking. That, by implication, logically confers upon the UK a right to respond to such arrangements by taking whatever action is necessary to safeguard the base, and our interests and those of our allies on the base. Can the Minister confirm that that is the Government’s understanding?

An important protection is granted to the UK by Annex 1, paragraph—

[Lord Hannay of Chiswick (CB)]

Forgive me for interrupting, but the noble Baroness said a few minutes ago that the sovereign base area in Cyprus was not the subject of a treaty. It was the subject of three treaties: the Treaty of Guarantee, the Treaty of Alliance and the treaty of establishment.

[Baroness Goldie (Con)]

I hesitate to correct the noble Lord. I think what I said in response to the point raised by the noble Lord, Lord Beamish, was that the sovereign base areas in Cyprus and this arrangement are not the same. The point that the noble Lord, Lord Beamish, made was, in fact, about expeditiously communicating with Cyprus if we are going to do something. With the greatest respect to the noble Lord, Lord Hannay, I thank him for his intervention but I think we are slightly on different planes.

I had got to the UK’s position under Annex 1, paragraph 1A, which says that the UK shall have

“unrestricted access, basing and overflight for United Kingdom and United States of America aircraft and vessels to enter into the sea and airspace of Diego Garcia”.

That is good. Annex 1, paragraph 1B(i), says the UK shall have “unrestricted ability” to

“control the conduct and deployment of armed operations and lethal capabilities”

on Diego Garcia. That is strong; it is a clear reassurance and there should be no ambiguity as to what it means. But less clear is Annex 1, paragraph 1B(viii), which says the UK shall have “unrestricted ability” to

“permit access, basing and overflight for non-United Kingdom and non-United States of America aircraft and vessels, upon notification to Mauritius”.

If that is merely a courtesy intimation then it does not compromise the UK controlling the conduct and deployment of armed operations and lethal capabilities on Diego Garcia. If that notification requires the consent of Mauritius then it most assuredly does, so can the Minister confirm that such intimation is purely a courtesy and that consent to the proposed action is not required from Mauritius?

Under Annex 1, paragraph 2, the UK

“agrees to expeditiously inform Mauritius of any armed attack on a third State directly emanating from the Base on Diego Garcia”.

It is in the middle of the Indian Ocean, and a territorial armed attack on a third state could theoretically be mounted from the base, albeit that is perhaps unlikely. Can the Minister confirm whether that obligation to inform “expeditiously” extends to assets which, for example, merely called into the base to refuel and are once again at sea or airborne? Does that obligation also apply if UK forces disable hostile aircraft, drones, ships or other devices which present a threat to the base?

I ask these questions because in any live conflict, the environment is kinetic. The last thing on the minds of military commanders will be seeking consents. These questions which I have posed require clear, unambiguous answers.

I turn to how the agreement engages with the Bill. I would have thought that the issues I have already raised, plus the importance of the role of the joint commission under Article 12 and the mechanism for setting disputes under Article 14, all merit a specific mention in the Bill. Can the Minister confirm whether the Government are prepared to look at the drafting of the Bill with a view to incorporating some of these issues into it?

Specifically, there is in the Bill a reservation to His Majesty under his prerogative to make laws for Diego Garcia and to empower His Majesty to make Orders in Council. I raised this at the very helpful briefing meeting held by the Minister, for which I thank her, but I will add this point. His Majesty is commander-in-chief of the Armed Forces. What if a threat to the safety of our Armed Forces manifests in the base itself or in the assets operating from there? If there is a disagreement with Mauritius as to the character and gravity of that threat and how the UK proposes to respond, does the lawmaking power under Clause 3(3) prevail to do whatever is necessary to protect our military and civilian personnel and our assets?

This agreement raises two profound concerns. First, if the Government concede this area of British sovereignty, how safe are our other crown territories—the Falklands, Gibraltar and our sovereign bases in Cyprus? The moment that lawyers come sniffing around any of those, will this Government be resolute and stand up to that? Secondly, this agreement should not be seen as some tying up of loose legal ends with a box ticked. It has a significant impact on the British taxpayer, on the Chagossians themselves and on our defence and security interests.

Notwithstanding the acknowledged authority of the noble Lords, Lord Browne of Ladyton and Lord Beamish, and the respect in which they are held in this House, the lack of support from the Government’s own Back Benches is troubling. I look forward to the Minister’s response, because this debate has raised a series of profoundly concerning substantive issues, and this Chamber needs reassurance.