Diego Garcia Military Base and British Indian Ocean Territory Bill

Baroness Chapman of Darlington Excerpts

Tuesday 4th November 2025 Lords Chamber

Moved by

[Baroness Chapman of Darlington]

That the Bill be now read a second time.

[The Minister of State, Foreign, Commonwealth and Development Office (Baroness Chapman of Darlington) (Lab)]

My Lords, the Bill that we are to discuss today is vital for the security of our nation. It enables the ratification and entry into force of the treaty between the UK and Mauritius concerning the Chagos Archipelago, including Diego Garcia, and thus protects the operation of an essential UK military base in the Indian Ocean. The consequences of not ratifying this treaty should not be underestimated. The inevitable effect would be to expose the UK to an unacceptable level of risk and legal uncertainty, which could deny us key military and security capabilities, dramatically reducing the effectiveness of our Armed Forces and security services. A binding judgment against the UK from an international court or tribunal would undermine our ability to operate globally to protect UK influence and counter the threats we face in an increasingly dangerous world, and it would put at risk security at home.

I understand that the treaty has divided opinion. We have had good debates in both this House and the other place on its substance, and I, of course, welcome this scrutiny. Since the Government signed the treaty, there have been Statements and debates across both Houses, hundreds of Questions raised and answered, and the completion of several committee inquiries by learned colleagues.

The necessity of the Diego Garcia treaty and of this Bill has been amply demonstrated. It has been tested in detail by the International Agreements Committee and the International Relations and Defence Committee. Both agreed that protection of the strategic value of Diego Garcia—a vital national asset—was necessary. The IAC clearly set out the path to significant risks to the base if the treaty were not ratified.

The Diego Garcia treaty has the support of our international allies. The United States has been engaged throughout the negotiations and supports it, as do the rest of our Five Eyes partners; Japan, South Korea and India support it as well. The UN, the Commonwealth and the African Union all welcomed it. Our overseas territories family supports it. The list goes on.

I welcome the opportunity to test this further today. The treaty is an important matter that the Government considered with great care. We bore the full weight of responsibility for not only the security of the British people but the integrity of the UK’s position on the global stage, and for respect for the experiences of those who had lived on the islands.

This treaty is critical to our national security. The base holds a range of vital capabilities, some of which are highly secret. I know that those with experience in this House will understand the military advantage of being able to deploy forces rapidly across the Middle East, east Africa and south Asia, and will appreciate the political and security importance of operating such a prized asset jointly with our closest partner, the United States.

The deal preserves this vital security footprint. With it, we will retain full operational control over Diego Garcia, with robust provisions to keep adversaries out. These include: unrestricted access to and use of the base for the UK and the US; a buffer zone around Diego Garcia; a UK veto to ensure that no development or construction on the outer islands threatens base operations; and a ban on the presence of any foreign security forces. The protections were designed, tested and endorsed at the highest level of the US political and security establishment.

The Government acted to protect this vital asset because it faced an existential threat. This was well understood by the previous Government, which is why they started negotiations more than three years ago—negotiations that they entered in good faith, despite what we heard in the other place, and continued for 11 rounds, including detailed text-based negotiations in the weeks and months before the general election.

It was under the previous Government that Mauritius secured its string of legal and political victories against the UK. Noble Lords will be aware of the International Court of Justice’s advisory opinion in 2019 and the loss of votes at the UN General Assembly. This was followed in 2021 by a ruling by a special chamber of the International Tribunal for the Law of the Sea on a maritime delimitation dispute between Mauritius and the Maldives. The special chamber, in a decision that was binding on the parties to the dispute, ruled that Mauritius’s sovereignty was inferred from the ICJ’s determinations. This gave a clear indication of how this tribunal—and, quite possibly, other international courts and tribunals—would approach the ICJ’s advisory opinion and the sovereignty dispute between the UK and Mauritius.

I urge noble Lords to reflect on the sound conclusions of the International Agreements Committee and the International Relations and Defence Committee. The learned members of both committees took evidence from eminent legal scholars, including a former member of the ICJ. The IAC concluded that, if the treaty is not ratified,

“Mauritius is likely to resume its campaign against the UK through international courts”

and stated that it heard evidence that

“any international court looking at this issue would be unlikely to find in favour of the UK”,

putting the base at risk.

The Government have been clear about the legal position. Had a long-term deal not been reached, it was highly likely that wide-ranging litigation would have been brought quickly against the UK. There were several potential routes for this, which included further arbitral proceedings against the UK under Annex VII of the UN Convention on the Law of the Sea. A judgment from such a tribunal would be legally binding on the UK. The United Kingdom’s long-standing legal view has been that we would not have a realistic prospect of successfully defending our legal position on sovereignty in such litigation. Even if we had chosen to ignore legally binding judgments against the UK, their legal effect on third countries and international organisations would have given rise to real impacts on the operation of the base and the delivery of all its national security functions. We have all heard the counter- positions—that the Government are bowing to an opinion that is merely advisory and that there was no viable route to a binding judgment—but I am afraid those simply do not reflect the reality of this situation.

It is clear that securing a deal was essential. The agreement that the Government have signed protects the base for generations and is firmly in the national interest. The Government did not secure the base at any cost; we negotiated a deal that is good value for money for the British people. The full financial details were published alongside the treaty on the day of signature. The average cost per year in today’s money is £101 million, and the net present value of payments under the treaty is £3.4 billion. These figures have been verified by the Government Actuary’s Department. These figures draw on long-established methodology, used under this Government and previous Governments, to account for long-term projects. We have all heard, and I suspect we will hear again today, the Opposition claim that the cost is higher. This is grossly misleading. Accounting norms and processes set out in the Green Book are there for a reason: so we can understand the true value of things. Let us debate those values with transparency, not exaggeration or manipulation for political point-scoring.

I suspect that some in this House will have heard concerns regarding undue influence on Mauritius from hostile forces. The Opposition were quite vocal on the subject in the other place—although, interestingly, we heard barely a peep before 4 July last year, when they were in negotiations. The treaty is the only way to ensure the base continues to operate as it has done, with all the protections that I listed earlier, including threats from our adversaries; whereas, had Mauritius secured a binding judgment against the UK, there would have been nothing to stop it leasing different islands to different countries, dramatically undermining the utility of this prized military asset.

As with any government policy, it is crucial that we discuss the people who are at the heart of it. I know there is a deep strength of feeling, genuinely held, in this House and the other place about Chagossians. Let me be clear: this Government deeply regret the way the Chagossians were removed from the islands. We are committed to building a relationship with the Chagossian community that is built on respect and acknowledgement of the wrongs of the past. The negotiations on the treaty were necessarily state-to-state between Mauritius and the UK, and it is true that our priority was to secure the base, but that does not mean that the interests of the Chagossian community were set aside. Indeed, the treaty has the support of many in the Chagossian community. Olivier Bancoult, chair of the Chagos Refugee Group, which is the largest Chagossian group, has said

“we remain convinced that this agreement provides the only way forward”,

and in a recent communiqué urged all Members of the UK Parliament to support the Bill.

The treaty provides that Mauritius may develop a programme of resettlement on the Chagos Archipelago, other than Diego Garcia, and noble Lords will also be aware of the £40 million trust fund for Mauritius to use in support of Chagossians. I know many in this House are interested in the operation of these commitments. My noble friend Lord Collins noted in this place that, ahead of ratification, the Government would make a ministerial Statement in both Houses providing a factual update on eligibility for resettlement and the modalities of the trust fund.

I know that many noble Lords are also interested in the environmental consequences of the treaty. It is crucial that one of the world’s most pristine marine environments is protected, and this Government and Mauritius are committed to that. Mauritian Prime Minister Ramgoolam has publicly stated his commitment to the marine protected area and confirmed it directly to the former Environment Secretary at the UN Ocean Conference in June.

Just yesterday, the Mauritian Government announced plans for the establishment of the Chagos Archipelago marine protected area. This will be based on the robust International Union for the Conservation of Nature categories for marine protected areas. Critically, it makes it clear that there will be no commercial fishing across the entire 640,000 square kilometre area. The Great Chagos Bank will be given one of the highest levels of protection, with the rest of the MPA categorised as a highly protected conservation zone. There will be limited provision for controlled levels of artisanal fishing in confined zones intended for resettlement to allow for sustenance of the Chagossian community, while maintaining the commitment to nature conservation. This development should assuage the concerns we have heard in this House and the other place about Mauritian commitments to environmental protections.

Despite this progress, and the passage of the Bill in the other place, there are still those here who want to relitigate the debate that we had in July. There are Motions intended to probe and amend at Committee and Report. They are welcome, but Motions that are designed to wreck are not about the welfare of a community; they are a cynical tactic of delay and disruption. The Opposition Front Bench has tried blocking ratification, yet seems unable to accept the will of this House. I am disappointed, but unsurprised, that we all now look likely to have to witness an unedifying spectacle of it having another go.

Noble Lords will notice that we are not considering a committal Motion to commit the Bill to Committee today. As noble Lords know, it is extremely unusual to table a Motion to seek to divide the House to delay the passage of government legislation passed by the House of Commons. It is even more unusual for the Opposition to press such a Motion to a vote on the Floor of the House, as they have indicated they would. We know that His Majesty’s Opposition take their responsibilities seriously. They have said on multiple occasions to my noble friend the Leader of the House of Lords that their motivation is to properly challenge and scrutinise government legislation. That is their job; it is not to block legislation or stop the Government getting their programme through.

Let me share the truth of this matter. The amendment to the committal Motion favoured by the noble Lord, Lord Callanan, is, in effect, a fatal Motion. I will explain why: it makes committal conditional on consultation. It is not credible to undertake meaningful consultation in the 30-day period set out in the Motion. It would therefore risk progress towards ratification becoming bogged down in litigation. The Front Bench opposite should know that; I would be surprised if they do not.

The Motion would wreck the Bill and mean a delay not of 30 days but of months, maybe years. In these circumstances, the Bill and the treaty that it is intended to implement could not move ahead. This is both reckless and deeply cynical. It is reckless because it threatens the continued operation of the base on Diego Garcia and, with that, the national security of the British people. It is cynical because the Opposition now seek to use, for their own ends, a community they systematically disregarded when in government. We all know their record: the decision not to consult Chagossians when meaningful consultation was possible at the start of negotiations; the decision in 2016 not to permit any resettlement by Chagossians across the archipelago; and the dramatic failure to spend 96% of the £40 million commitment to support Chagossians.

It is worth contrasting that record with the record of this Government. We are financing a new trust fund for Mauritius to use in support of the Chagossian community. We are working with Mauritius to start a new programme of visits for Chagossians to the Chagos Archipelago, including Diego Garcia. The treaty we have entered allows Mauritius to develop a programme of resettlement on the islands other than Diego Garcia. This Government are also increasing our support to Chagossians living in the UK through new and existing projects. These are initiatives that actually deliver for Chagossians; they are not empty promises or hollow words.

The Bill is relatively short. It preserves the current laws of the British Indian Ocean Territory as laws that will continue to apply to Diego Garcia once the treaty is in force, allowing for the base’s continued, effective operation with minimal disruption. The Bill also grants a new power to make the domestic legal changes needed to implement the treaty and to manage responsibly the base’s future operation.

There will be no change to the British nationality status that any Chagossian currently holds, whether it is a British citizenship or a British Overseas Territory citizenship, and current pathways for Chagossians to acquire British citizenship are also maintained. Most of the provisions in the Bill will commence only when the treaty enters into force. I trust that we will have a lively and thorough debate on this subject matter, and I look forward to debating the Bill’s contents. I beg to move.

[Lord Callanan (Con)]

My Lords, I thank the Minister for introducing the Bill, and I will come to some of her points shortly. This is now the second opportunity that we have had to debate the UK-Mauritius agreement concerning the Chagos Archipelago, including Diego Garcia, but it is of course the first time that your Lordships’ House has been asked to approve the agreement in law.

When we debated the Motion to approve the treaty under the CRaG process, I lamented the fact that the other place was denied the opportunity to have a substantive debate on the treaty at that point. If the Government are so confident in their arguments, why did they deny the other House the opportunity to debate this properly? As I said then, the Government played fast and loose with the conventions on treaty approval, despite promises that had been given by their own Ministers when the CRaG process was first introduced. The Government were elected on the back of pledges to put public service and integrity first; refusing to adhere to the conventions in this case hardly lived up to those promises.

That said, as a responsible Official Opposition—and recognising the primacy of the other place, which approved the Bill at Third Reading—we will not seek to deny the Bill a Second Reading today. We already know that the other place did not have the opportunity to debate the treaty when it was laid before the House, and the Bill subsequently received minimal scrutiny. In fact, Committee and Third Reading were both taken on the same day, and a total of just 17 hours of debate were allocated to a Bill that fundamentally changes our strategic security role in the Indian Ocean and puts £35 billion-worth of taxpayers’ money in the hands of politicians thousands of miles away from the UK.

Not only was there no mention of the Bill in the Labour manifesto; there was a specific promise to protect our overseas territories. For the election, the Minister’s party’s manifesto said:

“Defending our security also means protecting the British Overseas Territories and Crown Dependencies … Labour will always defend their sovereignty and right to self-determination”.


It seems that tax is not the only manifesto commitment being binned today.

Crucially, the views of the Chagossian people have not been heard. We feel it is only right that the Government should be required to consult the Chagossian community on the implementation of this treaty, including on the establishment of the Chagossian trust fund, which the Minister discussed. The UK taxpayer will fund it, but the Mauritian Government will have sole responsibility to distribute it however they see fit.

That is why I tabled the amendment to the original committal Motion that would have required the Government to consult the Chagossian community over a period of 30 days. If the Minister is concerned that 30 days is not long enough, I note that we talked about making it longer, but we did not do so because we wanted the Government to have the opportunity to get their Bill through this Session. If I had set the Motion at three months, the Minister would have told us that there is no time to have a Committee debate before the end of this Session because the Opposition are trying to deny them the Bill. We deliberately selected a short period so that the Minister could not argue that we were trying to wreck the Bill—that was not our intention. It was a measured, reasonable approach which we felt would have made up completely for the Government’s failure to consult the Chagossians to date and would help us in our work to give the Bill the proper scrutiny it deserves, informed by the outcome of that consultation. It was not a wrecking amendment, and the Minister knows that in her heart of hearts. Without that additional consultation—

[Baroness Chapman of Darlington (Lab)]

If the noble Lord was so concerned to do this, first, why did he not consult earlier? Secondly, he can achieve his aims—which would not be wrecking but would be perfectly legitimate —by amendment to the Bill, delaying implementation, perhaps. Those things are standard. He could make his case, or perhaps even win his vote, and achieve his aims, should they be genuine and not a wrecking amendment.

[Lord Callanan (Con)]

This treaty is due to last 100 years. How is it a wrecking amendment to take 30 days to consult the people who will be affected by it? The Minister is talking nonsense, and she knows it.

Without that additional consultation of the Chagossian people, we fear that the Bill, which received so little scrutiny in the other place, will go on to become law without the affected Chagossians having their views heard, as they rightly should. I know that a number of them have turned up to the Public Gallery to hear this debate today.

I hope that the Government’s decision to withdraw the committal Motion at the last moment is an indication that they are listening to us and want to think about this more deeply. It is clear to us that we need that consultation, so I call upon the Minister to bring it forward as part of the committal Motion when the Government eventually bring it back to the House. As I said, the Government intend this treaty to last 100 years; surely, we can take one month to consult the people most affected by it.

To call the Bill a surrender Bill is an understatement. This is a strategic capitulation that will see us give away sovereign territory that has been British for two centuries. To add insult to injury, taxpayers are paying tens of billions to Mauritius for the privilege of doing so. We know the important, strategic role that the British Indian Ocean Territory has played internationally as a staging post for forward operations in both the Indian Ocean and the Middle East. Handing over sovereignty, even with a lease agreement in respect of Diego Garcia military base, puts, in our view, that strategic role in jeopardy.

In particular, the requirement in the agreement that Mauritius must be informed of armed attacks on third states directly emanating from the base on Diego Garcia is an astounding failure of diplomacy. Could the Government tell us how this would actually work in practice, in a rapidly changing armed conflict? Has the US, which actually runs this base, agreed to do that? How would it work in practice? How would we inform them in an emergency situation, with proper notice to enable us to take strategic action, as required?

My noble friend Lady Goldie will expand on some of the security implications of this agreement, but we are clear that it is a capitulation that weakens our influence on the international stage. It is a surrender orchestrated by international lawyers and implemented by a Prime Minister who is either unwilling or unable to stand up for the UK national interest.

The Bill does not just relate to the UK’s affairs in the Indian Ocean; the sheer cost of the treaty with Mauritius makes the Bill a domestic issue, too. By pressing ahead with this legislation, the Government are facilitating an agreement that will see the UK pay almost £35 billion to Mauritius. I notice that the Minister spent quite a bit of her time disagreeing with those figures, yet only one hour ago, when I asked her how much of the ODA budget is being dedicated to this agreement, she got a cheap laugh, and avoided the question once again, as she has now done four times. However, she knows, as I know, that some of that ODA budget is being used to fund this agreement. If she wishes to be so transparent and disagree with our figures, why does she not tell us how much of it is going to be spent from the ODA budget? She can stand up and do it now, if she wishes.

[Baroness Chapman of Darlington (Lab)]

All of our ODA spending is published. It is probably one of the most transparent bits of government funding. I will send the noble Lord the website address so he can have a look and satisfy himself on this point.

[Lord Callanan (Con)]

I am grateful for that; that is a concession, of sorts. I have only asked her the question four times during Questions so far. Now that she is willing to be more transparent, that is progress, at least.

Against that backdrop, hard-working Britons will be furious that Ministers have somehow found £35 billion to send 6,000 miles away when we face such financial challenges here at home. The fact is that the treaty facilitated by the Bill will fund tax cuts for Mauritius while taxes are being hiked here at home. We put this deal on hold when we were in Government, when it was in its infancy. We saw its flaws, and we paused it. Alas, Ministers no longer have the clarity of mind needed to deliver for the British people and are—

[Baroness Chapman of Darlington (Lab)]

I am sorry, but that is factually incorrect and I would like to give the noble Lord the opportunity to correct it. It was paused, but when the noble Lord, Lord Cameron, was appointed Foreign Secretary, he restarted those negotiations.

[Lord Callanan (Con)]

I am happy to tell the Minister that I have spoken to the noble Lord, Lord Cameron, about that. He agreed that it was paused, which I think she has just confirmed.

Alas, Ministers no longer have the clarity of mind needed to deliver for the British people and, as so often with this Government, they have allowed themselves to be taken in by their international lawyer friends and donors. This all begs the question: why? Why did Ministers feel the need to pursue this agreement that puts Britain’s interests last? Why have the Government seen fit to saddle taxpayers with an additional financial burden, at a time when we are all being softened up for massive tax rises from the Chancellor of the Exchequer?

Ministers have told us, as the noble Baroness did again today, that this agreement is a legal necessity, but, as we heard from my noble friend Lord Wolfson of Tredegar when we debated the Motion to approve the treaty—I commend his speech to noble Lords who have not had the chance to see it yet—there is a range of views among very senior lawyers on this matter. The Government cannot hide behind legal advice, unless they want to publish it for us all to see. This was a political decision for which Ministers must take the political responsibility.

The almost single-minded obsession with international law has blinded the Government to the real threat from a country that itself pays absolutely no heed whatever to that same international law. We know that China has said that it wants to deepen its strategic partnership with Mauritius. As recently as 15 May this year, China’s ambassador to Mauritius said that the People’s Republic of China wanted to strengthen ties with Mauritius, noting the country’s “strategic advantages”, and expressed a commitment to elevating the bilateral strategic partnership. The Chinese ambassador to Mauritius is on the record as offering, unsurprisingly, massive congratulations on the deal and stating that China fully supports Mauritius’s attempt to “safeguard national sovereignty”. It is a shame that China does not show that same regard to the national sovereignty of other nations.

That is who the Government have appeased with this agreement. When the Government took office, they claimed that they would protect our national security. Can the Minister please explain how ceding national sovereignty to a country that is known to be deepening its ties with a nation that we know to be a threat to the UK will help them achieve that manifesto commitment?

As the Official Opposition, we will seek to amend the Bill in your Lordships’ House to ensure that the Chagossian community is properly consulted and that the agreement facilitated by the Bill does not put the desires of international lawyers before the interests of the British people, who have paid the taxes which are now to be transferred with careless abandon to Mauritius.

Speaking of the rights of the Chagossians, I find myself on this occasion in the unusual position of agreeing with noble Lords to my left when I say that the Government have not handled this well. In the other place, the Liberal Democrat spokesman, Dr Al Pinkerton, said that,

“this Bill fails the Chagossian people”.—[Official Report, Commons, 20/10/25; col. 756.].”

On this, we agree. Ministers have failed to properly consult the Chagossians to the point that the community is now furious with this Government, as we have all seen from our email inboxes.

However, there was another way. In the other place, the shadow Foreign Secretary, Dame Priti Patel, tabled a presentation Bill which included specific requirements

“to consult and engage with British Chagossians in relation to any proposed changes to the sovereignty and constitutional arrangements of the British Indian Ocean Territory”.

That is what should happen. The Chagossian community should be heard and not ignored.

In conclusion, the questions at the core of all our debates will remain these. Is this treaty a good deal for Britain? Does the Bill put us in the service of the British people? I do not think that it does—

--- Later in debate ---

[Baroness Chapman of Darlington (Lab)]

I start by thanking the noble Baroness, Lady Goldie, for her closing speech. It was exactly the kind of speech I would have expected from her. It was forensic and detailed, asking absolutely legitimate questions that any respectable Opposition should put to a Government proposing this kind of Bill. I will try to answer all her questions— I was writing as quickly as I could—but I may not get through them all. The idea of a letter in the Library, explaining the detail so that everybody can see what we have to say, is a very good one. I would be happy to do that.

I thank all noble Lords for their contributions. It has been lively, as I suspected it might be. I might say that I agreed with some contributions more than others, and some were probably better informed than others, but that is the nature of these things. I will endeavour to respond to all the points raised by noble Lords, and we will, I hope, have further discussions in Committee on many of those.

I would like to remind the House why we are scrutinising and reviewing a Bill sent to us from the other place. The Bill is essential to ensure that the treaty with Mauritius can be ratified, a treaty that is fundamental to safeguarding the operations of a critical UK-US base on Diego Garcia and to the security of British people. As the noble Lord, Lord Jay, said, the Bill is also vital to protecting the British citizenship rights of Chagossians.

Noble Lords have questioned the legal rationale for this deal and asked what court could give a binding judgment. Let me set this out again: as the noble Lord, Lord Hannay, explained well in his speech, if a long-term deal had not been reached, it is highly likely that further wide-ranging litigation would have been brought quickly against the UK. Both the International Agreements Committee and the International Relations and Defence Committee, in scrutinising the treaty, heard evidence of where these binding judgments could come from.

One possibility is that Mauritius would find a dispute under the UN Convention on the Law of the Sea that it could bring before an arbitral tribunal under Annexe VII of the convention. That also raises the prospect that Mauritius would seek provisional measures from the International Tribunal for the Law of the Sea. Provisional measures of this type and the decision of an arbitral tribunal would each be legally binding on the UK. A further possibility is that a dispute under a multilateral treaty could be brought before the International Court of Justice. A judgment delivered in the manner by the ICJ in disputes between states may also be legally binding.

There are those—we have had this ever since we started debating this issue—who question where this binding judgment might arise, but they are fundamentally missing the point here. The risk was real. International courts were already reaching judgments on the basis that Mauritius had sovereignty, and this in turn, as my noble friend Lord Browne explained, put the base at real risk. The point is that the treaty with Mauritius prevents that happening in the future.

Noble Lords are perfectly entitled to take a different view on the extent of that risk; that is absolutely their right. The Government’s view is that that risk is real. Having that view, any responsible Government making that assessment has to seek to resolve it and to come to some lasting, legally enforceable arrangement with Mauritius. That is why we did the deal. Noble Lords are entitled to disagree with the Government, and I have absolutely no issue with that, but please do not impute some sort of bad intent or motive around political correctness, colonialism or any of those things. Our intention is to secure that base for the benefit of the security of our country. We did it so an agreement could be concluded on our terms, rather than it being forced upon us so that we would have to accept the imposition of an arrangement that would not have been in our favour.

I am interpreting the questions from the noble Baroness, Lady Goldie, on the overseas territories as an invitation to the Government to restate their longstanding and clear commitment to all our overseas territories. The Conservatives, at some points in these debates, although not recently—the noble Baroness, Lady Goldie, never did this, but others did—would raise the issue of the Falkland Islands. I thought that that was the height of irresponsibility, and I am very glad that they no longer attempt to bring that question into these discussions, because it was wrong that they did that.

This treaty has a complex resolution process attached to it because it needs to be long-lasting, and we are trying to cover every eventuality that might arise. That is a really good subject for us to get into in Committee, and we must test that to make sure that we have got that right. I have every confidence that the noble Baroness and her colleagues will bring to us situations that we need to hold up against that process, to make sure that we have got that right.

On the notification of activities of third countries with our consent, there is a notification there. I think that is right, but it is not in any way conditional. We do not need consent. It is not about permission or any of those things. I hope that that is helpful.

On the ability to make law, we had an interesting discussion at the briefing about royal prerogative and the ability of the King to make law in Diego Garcia. We need to get into that in Committee. There will be things in the Bill that, when I was sitting in the noble Baroness’s place, I would have been asking questions about, such as powers and flexibilities, the ability of Ministers to make decisions, and the various methodologies. I expect we will be having long discussions about negative and affirmative procedures, for example, and law-making power is one such issue.

I want to address some of the points that were made regarding the Chagossian community. As I stated in my opening speech, this Government deeply regret how the Chagossians were removed from the islands. This is a community that the Government are committed to working with and supporting in the months and years ahead. I pay tribute to the noble Baroness, Lady Ludford. She made a compelling and genuine contribution on this important issue, as did the noble Lord, Lord Horam, and I commend those who have been working on this for very many years. She did her party proud, and I respect the longstanding commitment that she and others have had.

The Bill ensures that there will be no adverse impact on Chagossians’ nationality rights as a result of the treaty. Chagossians will not lose their current rights to hold or claim British citizenship, and no one will lose existing British Overseas Territory citizenship status. The Bill does, however, remove Chagossians’ ability to acquire British Overseas Territory citizenship in the future, because once the treaty comes into force, BIOT will not be an overseas territory.

On the trust fund, the noble Lord, Lord Horam, raised the possibility of an exchange of letters on the future treatment of Chagossians under this fund. This is, again, a genuine issue that we ought to explore. I appreciate that noble Lords will want more detail on how the trust fund will operate. I look forward to discussing this in Committee. Who knows? We might be able to reach some sort of agreement on that issue.

On the citizenship law, which was raised by one or two noble Lords opposite—it may have been the noble Lord, Lord Hannan—there have been mentions of section 76B of the Mauritian criminal code and concerns that Chagossians are leaving Mauritius for fear of being prosecuted for their affiliation with the UK. This is really important: no one has ever been prosecuted under this law; but just because no one has ever been subject to it, that does not make it right. Last week, the Mauritian Government repealed this section, and, as of April 2025, 94% of Chagossians with British nationality also had Mauritian citizenship.

On the right to self-determination, there have been questions during the debate, and leading up to it, about consultation with Chagossians. The negotiations on the treaty were necessarily between states—the UK and Mauritius—and it is true that we have prioritised the operation of the base on Diego Garcia. That has been our priority. There may be people here who disagree with that and who would have preferred us to prioritise other issues, and I respect their right to hold that view, but that is not the view of the Government. We wanted to protect the base.

There were some, including the noble Baroness, Lady Foster, who raised the right to self-determination for the Chagossians. I have followed the noble Baroness’s career for many years; I do not know why, but I have always been rather attached to following what she does and says, and I have a real long-standing respect for her. I completely understand why she wants to raise this issue, and why it matters so much to her. The fact is that the Chagos Archipelago has no permanent population and has never been self-governing. No question of self-determination for its population, therefore, legally arises.

The English courts, noting the conclusion of the ICJ in the 2019 advisory opinion, have proceeded on the basis that the relevant right to self-determination in the context of BIOT was that of Mauritians rather than Chagossians. Both the English courts and the European Court of Human Rights have considered, in a series of judgments since the 1970s, the related but distinct question of an alleged right of abode or other rights said to flow from that. On each occasion, the English courts and the European Court of Human Rights have ultimately dismissed these claims. The transfer of sovereignty, therefore, does not deprive Chagossians of any existing rights. This is a long-standing legal position that previous UK Governments have also adopted, including in claims brought as recently as 2020. That all sounds very legalistic and cold; nevertheless, that is the legal position as it stands.

[Baroness Foster of Aghadrumsee (Non-Afl)]

I thank the Minister for addressing this issue, because it has become a real touchpoint in the general populace. Does she agree that, while we might differ on the legality issue, there is a moral duty on the Government to engage with the Chagossians, who feel so let down, not just by this Government—I made that very clear—but by the whole political establishment in this country?

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[Baroness Chapman of Darlington (Lab)]

I agree, and I will say a little about engagement. It is an important point, and it deserves a proper response. If there is more that we can do, we would be very open to discussions about how it could be done in the right way that does not derail the process that we are trying to undertake about bringing the treaty into law.

Having said that, we recognise the importance of the islands to Chagossians, and have worked hard to reflect this in our wider policies. The noble Lord, Lord Purvis, has, as he said, a long-standing position on this which I understand and respect. His impressive command of the history of this subject was put to good use in his previous interventions. I completely agree with his point about the shameful treatment of the Chagossian population.

On engagement, in the past three years officials have met Chagossians and groups over 30 times to discuss the agreement and FCDO’s wider support to the community. The Minister for Overseas Territories, Stephen Doughty, has met with Chagossians four times since he has been in post since July last year and, on 2 September, the new Chagossian contact group met. It has wide representation from Chagossian communities in the UK, Mauritius, the Seychelles and elsewhere to give Chagossians a formal role that shapes decision-making in the UK Government’s support for their community. The group met for the first time on 2 September and will convene quarterly hereafter.

Claims that all Chagossians are opposed to the agreement fail to respect the differing views of this diverse and vibrant community. We have seen some of that reflected in our discussions this afternoon. Many voices support the outcome reached, and these include the Chagos Refugees Group, the Chagos Islanders Movement, the UK Natives Chagossian Council and the Seychelles Chagossian committee. However, I accept that there are many Chagossians who take a different view, which is their right.

On resettlement, points have been made that the treaty does not guarantee Chagossians the right of return to the archipelago and that it should have done. This has come up several times. In 2016, when in government, the Conservatives ruled out resettlement, acknowledging the acute challenges and costs of developing anything equivalent to modern public services on remote and low-lying islands. The KPMG report, which has been mentioned several times and was commissioned by that Government, concluded that resettling a civilian population permanently on BIOT would entail substantial and open-ended costs. This agreement gives Mauritius the opportunity to develop a programme of resettlement on its own terms without requiring the UK taxpayer to foot the bill.

There has been a range of views about Mauritius and its reliability. Some noble Lords have implied that Mauritius is somehow an unreliable partner that cannot be trusted. These claims are insulting to Mauritius, which is a member of the Commonwealth and a westward-facing country with shared democratic values. Mauritius ranks among the top African nations in governance, human development and innovation. It is a full democracy, a regional leader in human rights and a trusted partner in upholding the rules-based international order. It ranks second out of 54 African countries in the Mo Ibrahim index of African governance. It is also one of only two African countries not to have signed up to China’s belt and road initiative. As an act of good faith, Mauritius stopped its legal campaign against us while we negotiated.

Much has also been said about China. There has been a substantial amount of complete misinformation about China’s influence in the region and reported plans to develop a military base in the Chagos Archipelago. The Mauritian Attorney-General has stated publicly that these claims are a gross falsehood and calls them a political gimmick. I can confirm, unequivocally, that the treaty prevents any foreign security forces, civilian or military, from establishing themselves in the archipelago. Furthermore, if the UK believes, for whatever reason, that any activity taking place in the archipelago would jeopardise the security of the base, Mauritius is obliged under the treaty to co-operate with us to prevent that risk, and the UK can veto any construction or development across the archipelago which we consider to be a security threat to the base. As for claims that China supports the treaty because it grants it greater influence in the Indian Ocean, that is, frankly, nonsense.

This is why our closest allies and partners have welcomed the deal, especially the US and other Five Eyes partners. They are satisfied that the treaty protects the base against foreign influence and think that it is essential for our capabilities for generations to come.

Many of the points on the issue of the environment are really quite important, including on marine protected areas. The noble Lord, Lord Thurlow, made a thoughtful speech about this. There have been claims made, both during the debate today and in the other place, that the Mauritian Fisheries Minister wished to issue fishing licences in the area, which would risk, the argument goes, the protection of the unique marine environment of the archipelago. It must be noted that the point the Minister was making was more to do with sovereignty than with fisheries policy, but, as I said in my opening speech, the Mauritian Government confirmed only yesterday that they will establish a marine protected area that follows current bounds of the BIOT MPA and that they will not allow any commercial fishing in any section of the marine protected area.

Noble Lords have quite reasonably sought assurances on enforcement of the MPA, and I expect this is something we will get into detailed discussion about in Committee. For today, I point out that, if the UK at any point believes that Mauritius is in breach of its environmental obligations, we can seek to resolve that using the agreed dispute resolution mechanism in Article 14. In any case, the UK and Mauritius are working to finalise the arrangements on maritime security to ensure that there are patrolling capabilities and that these are maintained.

[Lord Callanan (Con)]

On the point about the marine protected area, I think the Minister said that Mauritius had duplicated the zone absolutely. Is it not the case that it is not a no-catch zone? Point B in the communiqué issued confirmed that fishing will still be permitted in over 600,000 square kilometres of the zone.

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[Baroness Chapman of Darlington (Lab)]

That is right, and I said that in my opening speech. This is about artisanal fishing. In the event of some sort of resettlement on the outer islands, those communities would need to sustain themselves. They would fish using traditional artisanal methods, and that is what the permission relates to. It would not permit any other form of fishing, because that would clearly be detrimental to marine life.

The noble Lord, Lord Beamish, chair of the ISC, said—and this is about money—it is disappointing that there continues to be reference to artificially inflated figures of the cost of the treaty. It is misleading to ignore inflation and the changing value of money over time. The net present value of the treaty is what we have always said it will be: £3.4 billion over its lifetime. This is in line with long-standing practice in how the Government account for all long-term spend. The Office for Statistics Regulation and the OBR have verified these figures and confirmed that we have applied this methodology correctly.

[Baroness Noakes (Con)]

My Lords, the point is that, in accounting for money, cash accounting is used in government. What she is talking about is economic analysis, which is not the same as financial analysis. If she had been in the Chamber she would have heard my speech on this subject. It is clear that, when we come to draw up accounts for the Government, cash goes into this in pounds expressed in the time expended.

[Baroness Chapman of Darlington (Lab)]

I apologise to the noble Baroness for missing her speech, and I will read it in Hansard; the bladder is only so strong. What matters here is that there is consistency across government and over time in the way that we do these things. These things are done the same as they would be done for any other agreement.

I know that some people take a different view of the OBR from the one that this Government take. We take it seriously, and it has looked at our figures and verified them. The noble Baroness could by all means come back to this in Committee—I am sure that she will—but, for tonight, I will stick with what the OBR had to say on this issue. The way that we have done this ensures that the figures are realistic and comparable, not inflated by simply adding up future payments while ignoring the depreciation of value over time.

The noble Lord, Lord Altrincham, made quite a thoughtful speech. He is worried about the money. I should point out that we do not see this as an open market situation by any means. He seeks clarity about total cost. I can confirm that £3.4 billion is just that—it is the total cost.

The noble Baroness, Lady Meyer, suggested that the US should be contributing to the cost of the treaty, given its joint use of the military base. We have to recognise that the US pays for the operating costs of the base, and these are several multiples greater than any payments by the UK. We benefit greatly from this arrangement. This allows us to access a valuable capability that keeps our country safe and the US is paying far more for it than we do.

[Lord Beamish (Lab)]

Does my noble friend agree that this agreement also allows the Americans to forward plan for their investment, which, as she quite rightly says, is substantial?

[Baroness Chapman of Darlington (Lab)]

Absolutely. I thought the point made by the former Secretary of State for Defence, my noble friend Lord Browne of Ladyton, added to this very well when he talked about how future investment is jeopardised by the legal uncertainty that we are seeking to resolve.

Some have questioned the use of defence money in particular for this treaty. To be absolutely clear, the cost will be split between the FCDO and the MoD, as is appropriate given the shared interests of both departments in maintaining the future of the base. As set out by the Defence Secretary in his Oral Statement on the treaty in the other place, the costs represent a fraction of a percentage of the total defence budget—less than 0.2%. It is a bit far-fetched to suggest that the annual payments are in any way comparable to the biggest uplift in defence spending that we have seen since the end of the Cold War.

The noble and gallant Lord, Lord Craig of Radley, raised sea level change. I do not know why I am dealing with this in the money section, but this is where I have written it down so we might as well get it on the record. As he said, it is true that sea level change has been less than 1% over the past 50 years, but it would be helpful for us to explore in Committee how a future sea level change, which he quite rightly alerts us to, would be treated by the dispute resolution process. I do not have a clear answer to that tonight but that is what Committee is for: getting to the bottom of exactly those sorts of questions.

I will give the last word to the noble Lord, Lord Kerr. He made the very strong argument—it is not one that I had thought of, but I will definitely use it again—that this House voted in July to ratify the treaty. The Bill facilitates the enactment of this House’s wishes, because we voted in favour of the treaty. The Bill is necessary so that we can complete the ratification with Mauritius and therefore secure the critical military base on Diego Garcia. I thank noble Lords for their contributions and look forward to debating this in Committee.

Bill read a second time.