Diego Garcia Military Base and British Indian Ocean Territory Bill

Debate between Lord Beith and Lord Callanan

Committee stage
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.