Diego Garcia Military Base and British Indian Ocean Territory Bill

Debate between Iain Duncan Smith and Jeremy Wright

2nd reading
Tuesday 9th September 2025 Commons Chamber

[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.