Diego Garcia Military Base and British Indian Ocean Territory Bill

Iain Duncan Smith Excerpts

2nd reading
Tuesday 9th September 2025 Commons Chamber

[Luke Pollard]

In just one moment.

The treaty provides for control over the movement of all persons and goods on the base, and for control over the electromagnetic spectrum used for communications. It ensures that nothing can be built within a buffer zone of 24 nautical miles without our say so, and it delivers an effective veto on any development in the Chagos archipelago that threatens the base—something that the previous Government failed to secure in their negotiations. It prohibits foreign security forces from establishing a presence on the outer islands.

[Sir Iain Duncan Smith (Chingford and Woodford Green) (Con)]

I congratulate the Minister on his new position

May I get one little moment of agreement here? The Government say they abide by the law. Given the opt-out that we had, the original judgment was specifically not found in law, because we did not allow the ICJ to rule on Commonwealth issues. The question is a matter of law, so if the Minister is suggesting to the House that other actions would have taken place, they would have been unlawful. In what world was it necessary to block off those by assuming that this was law? It was not lawful.

[Luke Pollard]

The Foreign Office and the Government published the Government’s legal position when the treaty was laid. That assessment says:

“The longstanding 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 any future sovereignty litigation. That important and long-standing view predates this Government. Again, it was one of the reasons why the Conservative Government began the negotiations and held 11 rounds.

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[Priti Patel]

I thank my hon. Friend for that intervention. I say gently to some Labour Members, who are laughing and sneering at a fellow Member of this House when she is making a very valid point, that they are simply being disrespectful. It says a great deal. The hon. Member for Dunfermline and Dollar (Graeme Downie) can laugh as much as he wants. The British public see Labour as a party that does not stand up for Britain and British values, and that is not something to be laughed or sneered at.

[Sir Iain Duncan Smith]

I am grateful to my right hon. Friend. Just to settle this whole argument about net present value, the reason it simply cannot be used for a long-term treaty obligation is that it is necessary to make a really heavy estimation of what will happen socially and economically in that area. It is just about possible to use some of that in the UK, where the Government control certain aspects, which they will not control after this treaty is signed. That is why it has been recommended that it not be used for long-term effects when not within the UK. That is why the actuarial department advised going for the total amount, not this net present value.

[Priti Patel]

My right hon. Friend is absolutely correct.

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[Sir Jeremy Wright]

I understand the point that my hon. Friend makes, and it is reinforced by the point made by our hon. Friend the Member for Harwich and North Essex (Sir Bernard Jenkin) in reading from the agreement as to how any disputes are resolved. But I want to focus on the position now and the legal justification that the Government have already deployed for the arrangement that they seek to make. My hon. Friend is right that there will be further problems down the road, but there are problems already.

It seems to me that if the position the Government take is as I have set it out and as the Minister accepts that it is, that must be right because it would surely be difficult to argue that, were it not for that legal uncertainty, renting Diego Garcia back from someone else would be better than owning it from a security point of view. So for the Government to persuade us in this House, and indeed the country as a whole, that this is a good deal for Britain, everything turns on the question of legal uncertainty, which Ministers have often referred to as the reason why the treaty, and therefore the Bill, are necessary.

Having spent four years as Attorney General, I am quite familiar with legal uncertainty—there is a lot of it about in Government. It is, I am afraid, invariably the case that whenever a decision is made in Government, someone disagrees with it, and some of those who disagree will be prepared to go to a court and challenge the validity of that decision. Until the court—sometimes until the Supreme Court—has resolved the matter, there can fairly be said to be legal uncertainty about it. Legal uncertainty hangs around Government like the clouds, and it cannot be allowed to paralyse a Government. Nor should that sort of atmospheric legal uncertainty be the only cause of a decision as significant as that which this Government are now making to give up sovereignty over a vital military facility.

There must be something more substantive—more tangible—to the legal uncertainty to which Ministers have referred. Many of us have tried to find out what exactly that is, but with very limited success. Given that, as far as I can tell, the legal uncertainty that is being talked about constitutes the entirety of the burning platform on which the Government rely to justify the Bill and the treaty, surely this House, before we approve either, must be given a proper and clear explanation of precisely what legal jeopardy the Government are acting in response to. In pursuit of that, it is worth having a look at the explanations that Ministers have given so far.

Let us start with the former Foreign Secretary, the right hon. Member for Tottenham (Mr Lammy), who of course is now the Deputy Prime Minister. He made a statement on the British Indian Ocean Territory negotiations on 7 October last year. He told the House that the issue of contested sovereignty over Diego Garcia was becoming more acute, and that

“A binding judgment against the UK seemed inevitable”.—[Official Report, 7 October 2024; Vol. 754, c. 45.]

Many of us have been asking where that binding judgment might come from. The only court that had by then been mentioned was the International Court of Justice, which had issued an advisory opinion on sovereignty over the Chagos Islands and Diego Garcia. Indeed, on this subject it could only have been an advisory decision, because the UK accepted the compulsory jurisdiction of the ICJ by declarations dated 22 February 2017—I was Attorney General at the time. Those declarations made it clear that the UK did not, however, accept that compulsory jurisdiction in relation to

“any dispute with a Government of any other country which is or has been a Member of the Commonwealth”.

That involves and includes Mauritius, so any dispute with Mauritius before the ICJ could not result in a binding judgment against the United Kingdom. That point has been put to Ministers and, as far as I know, they have not dissented from that analysis.

If the ICJ could not make the binding judgment that the former Foreign Secretary told us was inevitable, which other court might? On that, again, I am afraid that we have not had clarity. On 13 November last year, the Minister of State at the Foreign, Commonwealth and Development Office, the hon. Member for Cardiff South and Penarth (Stephen Doughty)—who I see has the misfortune of having to defend this position once again today—answered an urgent question on the Chagos Islands. He said:

“International courts were reaching judgments on the basis that Mauritius had sovereignty over the Chagos archipelago.”—[Official Report, 13 November 2024; Vol. 756, c. 793.]

The Minister did not at that point say which courts, but I have done some digging, and I think I am supported in my assumption by what the Minister of State, the hon. Member for Plymouth Sutton and Devonport (Luke Pollard), said in opening this debate. I think that he may have been referring to a determination made in January 2021 by the special chamber of the International Tribunal of the Law of the Sea when considering a dispute between Mauritius and the Maldives. Tragically, I do not have time to go into the fascinating detail of that case, but in essence it was a dispute about the delimitation of maritime territory between those two states. The Maldives argued that the special chamber could not determine the case in question because there was an ongoing dispute about the sovereignty of the Chagos Islands between Mauritius and the UK. The special chamber decided, however, that it could treat Mauritius as the coastal state in the dispute before it, because of the ICJ’s advisory opinion on the matter, which it said had legal effect.

If that ITLOS case is what the Government are relying on, I think there are a few problems: first, the UK was not a party to that case; and secondly, the ITLOS chamber was seemingly basing its decision on that of the ICJ, which, as I have already indicated, could not make a binding ruling on the matter. I am not expecting the House, much less the Government, to accept my opinion on this, but it seems to me that, at the very least, the UK would have the basis of a decent legal argument here. It does not seem to be that this ITLOS decision demonstrates that there was no further hope for UK claims of sovereignty over Diego Garcia.

After a bit more prodding, the Government’s argument moves on and introduces the issue of access to the electromagnetic spectrum. On 5 February this year, the Minister of State at the Foreign Office answered yet another urgent question on the subject.

[Sir Iain Duncan Smith]

Before my right hon. and learned Friend moves on to the spectrum, may I bring him back to UNCLOS? As I understand it, article 298(1)(a) and (b) give us specific exemptions from UNCLOS judgments across all those areas. That is relevant to the UK in

“disputes concerning military activities…by government vessels and aircraft…in non-commercial service, and disputes concerning law enforcement activities”

in those areas. On that, the Government’s argument on UNCLOS falls, surely.

[Sir Jeremy Wright]

I will give my right hon. Friend a lawyer’s favourite answer to any question: “It’s complicated.” But here is the point: the only legal analysis being offered here—the only explanation—comes from the Opposition Benches. The Government are not giving us anything. If he is wrong in what he says, we need to hear why from the Minister, but we are not and that is what troubles me.

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[Sir Iain Duncan Smith (Chingford and Woodford Green) (Con)]

Just to make a small comment on the previous speech, I have been here a little while, and I have never once stopped regretting taking a Government handout to speak in support of the Government, because more often than not, it rebounded on me. As my right hon. and learned Friend the Member for Kenilworth and Southam (Sir Jeremy Wright) and many others have made clear, there are two elements to this issue.

Before I start on that, I want to say something about the Chagossians. They are the last people to have been seriously consulted about any of this. The way that we behaved to them back in the 1960s was appalling. It should never have happened, and there was no need for it to have happened. They should have been able to stay on the archipelago, and we should have supported them in that. They must be a part of this. I know that they are very fearful of this deal as it stands.

My other point is that this arrangement is vague about what happens after 99 years. We are supposed to guess, or believe that we can trust Governments to make the right decisions. The statement on the rights of the Chagossians is completely missing a sense of where they will be, what they want and how we will bring that about. I pay tribute to the Member who made a good intervention on that point.

Let me quickly deal with the legal case, and then I will discuss the cost, and China and Russia. The Government have been peppered with requests non-stop since this process began to explain the legal threat that meant that we would be in real trouble if we did not seal a deal—any deal. Right the way along, they would not exactly explain. There were little suggestions here and there that a judgment would lead to certain things. My right hon. and learned Friend the Member for Kenilworth and Southam has been absolutely right on that.

Today, I thought that the door slightly opened. I have known the Minister of State, Foreign, Commonwealth and Development Office, the hon. Member for Cardiff South and Penarth (Stephen Doughty), for a long time, and his name is a good description of his solidity and purposefulness. The Minister who opened the debate, the hon. Member for Plymouth Sutton and Devonport (Luke Pollard), made the point that the legal threat was to do with UNCLOS. I was intrigued by that, because, as I just said to my right hon. and learned Friend the Member for Kenilworth and Southam, within UNCLOS, clear for all to see, is a complete let-out for the UK Government when it comes to the case that they suggest would be brought against them under UNCLOS. The threat simply does not exist. I repeat that there are two exemptions, under article 298(1)(b) and 298(1)(c). The first has the UK opted out of

“disputes concerning military activities…by government vessels and aircraft engaged in non-commercial service, and disputes concerning law enforcement activities”.

The same applies under 298(1)(c) in relation to matters taken up by the UN Security Council.

The important point is that the threat does not need to be recognised, because ultimately this comes back to the original International Court of Justice ruling. That was an advisory judgment, because the Court cannot make an absolute judgment on anything to do with our relationships with the Commonwealth, either existing or previous; that is an important point. We keep coming back to this check on what would happen. The idea that everybody will dispute with us on that is simply nonsense. From a legal perspective, I think the Government have come unstuck in this debate. I have sat through many debates in this House, and it is rare that a Government completely come unstuck on a case of legalities.

The second bit that the Government have come unstuck on is the money. On the legal side, they will not tell us exactly what the situation is. There have been hints, proposals and suggestions that somehow we were in a desperate situation. On the money, I have never seen a Government as unable or unwilling to tell us exactly how much things cost or are worth. They are normally quick to do so, and to blame the other side, or whatever—it does not really matter. Everybody has been chasing the Government for that information, and now we discover that they have gerrymandered the figures for the overall statement. The total cost is nearly £35 billion, and we need to deal with total cost.

Let me remind the Government of the problem with what they call the GDP deflator and the so-called social time discounting method. The Government Actuary’s Department has dismissed that as a real way of calculating cost for this kind of issue, and it has re-emphasised the fact that understanding the total cost is the only way to look at a long-term treaty. The Government is relying on the cost-benefit analysis used for social projects. There is particular concern about long-term projects, and a real dispute about whether such a method can predict precisely, or even reasonably well, the overall cost in the long term. There is a lot of concern about whether that is the right way to go. Add to that the fact that the Government are trying to predict what will happen in Mauritius, under the Mauritian Government, over the next many years. This is a 99-year deal, and there is no way on earth that we have any control.

[Tom Tugendhat]

I wonder whether my right hon. Friend can help me in giving a prediction. Two families have swapped leadership of Mauritius over the last 60 years. Does he see any reason to doubt that the same two families will swap leadership over the next 60?

[Sir Iain Duncan Smith]

That is exactly the point. There are serious concerns about the uncertainties surrounding future growth and societal wellbeing. If there are such concerns when it comes to UK predictions about the UK, imagine how difficult it is to predict what will happen in Mauritius, so this should be dismissed.

It is interesting that after not answering the question for so long, suddenly the Government have popped up with a new device. They say that if we do not accept the figures, we are completely dismissing the Green Book, but the overall cost is not a Green Book issue, because this is about paying somebody money outside the UK, not about controlling cost. That is why the Green Book has never been used for this purpose before, and never will. I simply say to the Government that the money side of this has fallen apart again.

I come to the third element. As I said earlier, we have had no real vote or debate on the treaty, as opposed to the Bill. The old CRaG system has been rushed through, without a vote. I have to tell the Minister, for whom I have a huge amount of respect, that that is simply appalling, given that we are dealing with something as strategically important as this treaty.

Clause 5 of the Bill, which is a very flimsy document, is entitled “Further provision: Orders in Council”. Anybody who reads that will have a sudden intake of breath. The whole point of this Bill is negated by clause 5. What is the point of debating the rest of the Bill, given that clause 5 says that at any stage, and under any circumstances, the Government can change it all by Orders in Council? Absolutely everything can be changed by Orders in Council, with no vote and no dispute. If the Government decide to go in a different direction, they do not have to consult Parliament any more.

The sweeping powers in the Bill are ridiculous. When the Minister was in opposition, he used to spend his whole time moaning—quite rightly—about Governments who give themselves such powers. Even by the standards of previous Governments, this Bill is pretty astonishing. It is a massive sweep. This is not really democracy any more; it is monocracy. In other words, we have given up debate and dispute, and we have handed things over to one person—the Prime Minister. I say to the Government that the Bill is appalling, and they really need to rethink it. We simply cannot go through with something as appalling as this. I can remember the Maastricht debates, and various others in which we spent a long time debating clauses on the Floor of the House. That was the right thing to do, because such issues are important. International treaties are vital to our wellbeing, and the Bill simply does not work.

The last thing I want to say is on China. I would say this, because I am sanctioned by China, as are some of my hon. Friends. I suspect that others will be sanctioned as well in due course. If they carry on working with me in the Inter-Parliamentary Alliance on China, they are bound to be sanctioned, and I look forward to their joining us at that table. There is no way on earth that China does not benefit from this Bill. China has its eyes on the very important flow of commercial traffic that runs just below the Chagos islands, which it has always wanted to be able to block, control or interfere with.

The Chinese already have a naval base in Sri Lanka, which they got by default on the back of the belt and road initiative, due to non-payment. For a long time, they have been looking at how, under their arrangements with Mauritius, they will eventually be able to intervene. They are two or three steps further forward as a result of this Bill. It does not secure us against that absolutely, because we gave up absolute security and control when we decided to hand over sovereignty to Mauritius.

[Cameron Thomas]

I am not yet on the Chinese Communist party’s sanctions list, but perhaps I will be shortly. Does the right hon. Member share my concern about the 99-year lease of the islands, given that some of our adversaries across the world plan and strategise over the very long term, and 99 years is actually a short period of time?

[Sir Iain Duncan Smith]

The hon. Gentleman is absolutely right that the Chinese Government have a long-term plan. In fact, they are very clear about what they wish to do. If anybody does not think that China poses a threat on all these issues, what were they doing last week when, on our television screens, we saw President Xi, with the North Korean dictator on one side and the Russian dictator on the other, talking about a new world order? That continues to be the Chinese Government’s purpose. They should have been taken into the upper tier of the foreign influence registration scheme. Why are they not there? My suspicion is that this was not done because it might well have ended the whole negotiation on the Chagos islands, as there would have been huge interventions, and we could not possibly have done aught else but stop the negotiation.

In conclusion, I honestly think that the Government need to pause this, go back to the drawing board, and say, “We got it wrong”, but I say this in answer to the endless briefing they have given Labour Members on what the Conservative party did about the Chagos islands in government. I have reached the conclusion that no matter who is in power, I am in opposition, so I can categorically tell the House that, whatever else happened, this was quite rightly ended by Lord Cameron when he became Foreign Secretary. Some of us made it very clear that this should not have gone ahead for many of the reasons that I have laid out. I end by saying to the Minister that it is no good coming back later and saying, “I wish we hadn’t done this.” Now is the time to stand up and say, as the hon. Member for Crawley (Peter Lamb) did, that this does not work, it must stop, and the Government must think again.

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[Dr Luke Evans (Hinckley and Bosworth) (Con)]

May I say how much of an honour it is to follow the right hon. Member for Islington North (Jeremy Corbyn)? Although we do not necessarily agree on a lot of policy, I am always struck by the fact that he puts people at the heart of his speeches. That has never been the case more than during his long campaign on this issue, on which he spoke eloquently. He is putting Chagossians right at the heart of any decision making. He deserves a lot of acclaim for that. He is right to call out some of the rhetoric in this debate, because, at the end of the day, those people really matter. I thank him for putting his points on the record.

There are three broad areas that I would like to cover: sovereignty, costs and some of the scariest parts of the Bill. I listened to my right hon. and learned Friend the Member for Kenilworth and Southam (Sir Jeremy Wright), and I must admit that I am not nearly as learned or experienced as him; I bow to his legal analysis. I am a mere doctor, so I look for an evidence base when trying to understand the process. To that end, I thought it would be useful to write to the Foreign, Commonwealth and Development Office, which I duly did. I received a letter on 28 July 2025 from the Minister of State, Foreign, Commonwealth and Development Office, the hon. Member for Cardiff South and Penarth (Stephen Doughty), who I see will kindly respond, and is sat in his place. Much to my surprise and pleasure, a lot of what is in the letter was in the Minister’s speech. This debate allows me to walk through some of the letter and pose the questions that hit me as I looked into this case.

I must admit that when I stepped into this House in 2019, this was not a topic that I knew a huge deal about—I think many Members on both sides would say the same—but it very quickly became a topic that I realised we should look into understanding, especially as it deals with security.

The letter states:

“We had to act now because the base was under threat.”

That implies urgency, but the letter is loose on who was under threat, where and how. There is legal uncertainty but, as we have heard, we do not know which court is involved or why. It goes on to say:

“The courts have already made decisions which undermine our position.”

Courts, plural. We know that the ICJ is involved, but as has been stated, its opinion was non-binding, and there is a carve-out relating to the Commonwealth.

The Minister of State, Ministry of Defence, the hon. Member for Plymouth Sutton and Devonport (Luke Pollard), said, after being pushed to speak on the matter multiple times, that the International Tribunal for the Law of the Sea was the area of concern, but he will know that back in 2015, under annex VII, the tribunal agreed with the UK that sovereignty could not be determined by UNCLOS. This was a marine protection issue. Britons were trying to protect the area, and Mauritius wanted to open it up to farm it, and we were found against, under that treaty, in that court. This raises an important side issue: what protections are there in the Bill for the environment? They seem scant, or just not there.

The letter goes further, stating that

“in 2021…a Special Chamber of the International Tribunal for the Law of the Sea…ruled that Mauritius’ sovereignty was inferred from ICJ”.

So the Government themselves point that out. The letter goes on to say:

“The UK was not party to this case”.

Well, obviously, it would not be, but that means that we have not had our day in court to explain why we do not think that the judgment should apply. Mauritius’ sovereignty was inferred from that non-binding, political judgment.

The letter goes on:

“If Mauritius were to take us to court again, the UK’s longstanding legal view is that we would not have a realistic prospect of successfully defending its legal position on sovereignty in such litigation.”

Well, which court? If this advice is so long-standing, why do we not know about it? How have we got this far, going for year upon year with no agreement, without any urgency? It seems sensible and appropriate to release the advice on this. At the start of that quote, the letter said “If Mauritius”. It states later that it is

“highly likely that further wide-ranging litigation would be brought quickly by Mauritius against the UK.”

What evidence do the Government have to back that up? What is it that they say Mauritius will act so quickly on? We certainly have not seen it, if it was from 2021. The dates 2023 and 2024 have been mentioned, and we are now in 2025. I would be interested to see the Government release the evidence base for their claim about how quickly litigation would come forward, because as they rightly point out, there have been 11 rounds of negotiations, so there has clearly been time to sort things out.

Before someone jumps in and says, “Well, you opened the negotiations”, I would point out that we did that for the Falkland Islands as well. I find it amazing that we have trade unionists who built their whole careers on negotiating suddenly chastising the Conservatives for listening to the other side of a disagreement. That seems bizarre to me, because we want to respect each other and exchange ideas, but not have an agreement. It is rightly pointed out by Conservative Members that the agreement was not there; we did not take it. On the cost of the deal, there is no cost, because we did not have a deal to sign off.

The very next sentence in the letter says:

“This might, for example, include 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.”

[Sir Iain Duncan Smith]

It is not.

[Dr Evans]

It is. It is true about the legally binding aspect within the area that the tribunal covers, but that does not cover sovereignty, as we learned in 2015 when the tribunal sided with the British Government. Here we have the farcical situation of a House of policy and law shining light on one side and another, but never on the truth. This is where my right hon. and learned Friend the Member for Kenilworth and Southam is exactly right. If the Government were to come forward and say exactly which court, where and why, they might get more sympathy from Opposition, but we have been through an entire five-hour debate and we still do not have answers to those questions.

Another court that is often cited is the International Telecommunication Union covering spectre, radio and radar. Article 48.1 states

“Member States retain their entire freedom with regard to military radio installations,”

and the Government know that. Even the written answer from the Minister—it has been hinted at before—states:

“Individual countries have the sovereign right to manage and use the radio spectrum, within their borders, the way they wish, subject to not causing interference with other countries. This right is recognised in the Radio Regulations. The Radio Regulations are the international framework for the use of spectrum by radiocommunication services, defined and managed by the International Telecommunications Union (ITU). Individual countries, not the ITU, make their own sovereign spectrum assignments in accordance with the Radio Regulations. The ITU has no legal authority over these assignments regardless of the country’s civilian or military classification of spectrum. The ITU cannot challenge the UK’s use of civilian or military spectrum.”

It is clear here—the Government know it in their own answers—that the ITU has no role in sovereignty. It all boils down to where one believes British overseas territories stand.

Now we must talk about the cost, which has been much debated. There have been three figures in the debate: £3.4 billion, £10 billion and £34 billion. The £3.4 billion is the net present value using social time preference rate. The £10 billion is inflation adjusted, and the £34 billion is the nominal value by the Government Actuary’s Department. The question is, why use net present value? I put it earlier in the debate that there is no other precedent in the world for NPV being used in sovereignty matters. The Minister at the time asked whether the Conservatives want to do away with using NPV—of course not.