Diego Garcia Military Base and British Indian Ocean Territory Bill

Lord Beith Excerpts

Tuesday 18th November 2025 Lords Chamber

[Lord Callanan (Con)]

My Lords, Amendment 6 is linked to Amendment 79 in this group. Amendment 6 would link the Bill’s effect to the treaty. If we were to make this amendment, the moment the treaty ceased to have effect, so would this legislation. Amendment 79 would require the Government to publish a statement of their understanding of the legal status of the Chagos Archipelago, should the underlying treaty be terminated.

The reason behind these amendments is that the wording of Clause 2, which would stand on the statute book even if the treaty itself were revoked, is clear only that:

“His Majesty is no longer sovereign over”


the Chagos Archipelago. However, it does not state that Mauritius would be sovereign over the archipelago. The Hong Kong Act was worded similarly and did not grant China sovereignty; it merely revoked Her Majesty’s sovereignty. This means that the only document establishing Mauritian sovereignty over the islands is the UK-Mauritius agreement. If that agreement were terminated, what would be the status of the islands? That is the question that we are putting to the Government.

Interestingly, it is not the case that we could not state in the Bill that Mauritius has sovereignty. There is precedent for that, and it would perhaps state the position more clearly. If noble Lords cast their minds back to the Heligoland–Zanzibar Treaty of 1890—which saw Britain cede sovereignty of Heligoland, a series of islands in the North Sea off Schleswig-Holstein—they will remember that that was in exchange for a free hand in respect of the independent Sultanate of Zanzibar. The Anglo-German Agreement Act 1890, which gave effect to that treaty, stated specifically, in the Schedule, that

“the sovereignty over the Island of Heligoland, together with its dependencies, is ceded by Her Britannic Majesty to His Majesty the Emperor of Germany”.

Can the Minister explain why the Bill follows the example of the 1985 Act and not the clearer precedent of the 1890 Act?

My noble friend Lord Lilley’s Amendment 12 seeks to deliver clarity that the UK can regain sovereignty. That would be a better outcome than an explicit statement that Mauritius will have sovereignty in perpetuity. Whatever the Government’s position on the legal status of the archipelago under this legislation, I believe that, either way, we deserve some clarity.

My Amendment 77 also seeks to resolve a lack of legislative clarity that arises from the fact that the Bill is implementing the more detailed treaty. The treaty provides for the creation of a joint commission, but we have precious little detail on the commission. My amendment would require the UK Government to set out the process that they intend to follow, alongside the Government of Mauritius, to establish the commission. I am sure that the Government will resist the amendment, but I hope that there will be an opportunity for the Minister at least to set out the Government’s expectations of the process that will be followed. Can the Minister say where, when and how often the commission is expected to meet? Who is expected to be appointed to represent the UK Government on it? Will they be a political appointment or a civil servant, and how will they be appointed? I assume that we will have a senior representative, but if the Minister could tell us who or what it might be, that would aid the Committee in its consideration of the Bill.

These are all very important questions that should be answered before we proceed with the Bill. So far, the Government have sought to avoid debate, resisted consultation and prevented transparency, but I hope the Minister can do better in her response to the amendments in this group. I beg to move.

[The Deputy Chairman of Committees (Lord Beith) (LD)]

My Lords, if this amendment is agreed to, I will be unable to call Amendment 7 by reason of pre-emption.

[Baroness Goldie (Con)]

My Lords, I will speak to Amendment 89 in my name and in support of the amendments in the name of my noble friend Lord Callanan.

At Second Reading, I raised the broad issue of the royal prerogative, and the Minister is aware of my, perhaps inquisitive, interest in that. That broad power is in Clause 3, and the specific reference to His Majesty’s power to make Orders in Council comes in at Clause 5, particularly in Clause 5(1)(a). That is powerful. For the benefit of the Chamber, I repeat what that says:

“His Majesty may by Order in Council … make any provision that appears to His Majesty to be appropriate as a result of the Treaty”.


The following paragraph goes on to explain that that can be a

“consequential, supplementary, incidental, transitional or saving provision in relation to … this Act, or … an Order under paragraph (a)”.

I want to thank the Minister for her letter, which she very kindly sent to me yesterday. In it, she alludes to this particular issue and says that “Clause 5 of the Bill creates a new statutory power for His Majesty to make such provision by Orders in Council as he considers appropriate as a result of the treaty”. This led to my Amendment 89, because I am just trying to seek clarification of this power. In particular, I want to establish whether that power can be used by His Majesty, for example, to withdraw the United Kingdom as a party to the treaty and withhold any payment due to Mauritius if Mauritius violates any terms of the treaty.

This is not a lengthy matter for discussion. In responding, I would ask the Minister, if she opposes my amendment, and I anticipate that she may, to be specific about the ground of objection. It may be that she says, “I don’t want the Secretary of State being mixed up in anything like this, it’s just unnecessary and tiresome and he’s got enough on his plate without being burdened with all that”. On the other hand, she might consider that this is an incompetent use of the royal prerogative. I would be interested in understanding that better.

It would be more alarming if the Minister said that she does not consider that, if Mauritius violates any terms of the treaty, the UK will be able to withdraw and cease payment. It is rather along the lines of the point raised by the noble and gallant Lord, Lord Craig, who is not in his place. There is a basic issue about whether the thing is working or not. In his case, the thing is not working because the base has disappeared under the ocean. In the dim and distant past in contract law there was something called “frustration of the contract”: if the underlying purpose disappeared, the contract evaporated. The Minister has undertaken to investigate that further and we shall await that.

I really want to understand, if Mauritius violates the treaty, what practical solution is available to the UK: whether it is paying the money, coming out of the treaty or taking whatever other remedial action is necessary. I shall look forward to the Minister’s response.