British Sovereignty Protection (Chagos Islands) Bill [HL]

Debate between Baroness Winterton of Doncaster and Lord Murray of Blidworth

Friday 23rd October 2026 Lords Chamber

[Baroness Winterton of Doncaster (Lab)]

I will come on to address that issue. Let me first return to what I was setting out, which is that, because of the legal position—which, as I say, I will come back to—negotiations were started by the previous Conservative Government. There were 11 rounds of talks, conceding the principle of UK sovereignty and establishing the model of direct payment to Mauritius to lease back Diego Garcia.

When they came to power in 2024, the Labour Government inherited a draft treaty that was close to completion and a political context in which the risk to base operations had never been greater. Nevertheless, the Government were able to secure much stronger provisions in the treaty to protect the base well into the next century. I should say that in drawing this up, the UK and the US worked hand in glove in developing the treaty, and we continue to work together. When the Diego Garcia treaty was signed by Prime Minister Keir Starmer, we had US support. However, as the noble Lord, Lord Weir, said, it is clear that the US, through President Trump, has taken a different view, so we will continue to work together, as has been made clear by both the Defence Secretary and the Prime Minister. We need the support of both Mauritius and the US to find a solution that works for everyone.

The noble Lords, Lord Callanan, Lord Lilley, Lord Bellingham and Lord Hannan, asked why we are handing over sovereignty on the basis of a non-binding legal opinion. This is not just about a legal judgment; it is about the long-term safety and security of the UK. The only way to maintain the base safely in the long term is through this agreement. There is no alternative, whereby we just hang on to the base without an agreement. The previous Conservative Government tried to do that under Boris Johnson and when that failed, they started the negotiations.

I accept that there are those who argue that we should ignore the legal challenges, but there is no question that we can do that. Doing nothing is simply not an option and threatens the UK’s safety. Some argue that there are carve-outs and exemptions that the Government have missed. We have heard these arguments before, and I am afraid we have to reject them. On the ICJ exemption, although the 2017 amendment does indeed mean that the International Court of Justice cannot rule on disputes between the UK and Commonwealth countries, this is not the only viable route to a binding judgment and not the one we consider most likely.

With regard to the UNCLOS—

[Lord Murray of Blidworth (Con)]

Can the Minister identify what those other potential sources of judgments are, rather than just alluding to them?

[Baroness Winterton of Doncaster (Lab)]

There is a misunderstanding of the legal position on Article 298 of UNCLOS. This does not create an exemption in respect of military bases, but in respect of disputes concerning military activities. As I say, there are other routes through international legal judgments that could be quickly translated into UK domestic proceedings.

Moving on to the issue of the Chagossians, raised by the noble Baroness, Lady Meyer, and the noble Lords, Lord Hannan, Lord Weir and Lord Callanan, I share noble Lords’ strength of feeling about the Chagossian community and the injustices they have experienced, and we have heard some very powerful contributions on that during today’s debate. Let me say again: the Government deeply regret the way the Chagossians were removed from the islands, and we are committed to building a relationship with the Chagossian community that is based on respect and acknowledgement of past wrongdoings.

However, we have to accept and respect the fact that there is a diversity of opinion within the community. We continue to engage with the Chagossian groups. The noble Lord, Lord Callanan, asked when the contact group last met; it met last week. We will continue that process of consultation.

On the Bill and the call for a referendum, which the noble Lord, Lord Bellingham, and others raised, I am afraid that we reject the Bill’s call for a referendum. The decision to enter into a treaty is a matter of national security, so we have to be very careful about how we approach that. That is why, while rejecting a referendum, we have taken concrete steps to help the Chagossians, including protecting British citizenship rights, increasing UK support and negotiating a treaty which would enable Mauritius to develop a programme of resettlement, which the noble Baroness, Lady Meyer, referred to, on islands other than Diego Garcia.

The noble Lord, Lord Bellingham, mentioned the environment. Although national security was paramount in negotiating the treaty, we also secured a deal that would continue to protect the unique environment of the Chagos Archipelago. We agreed to work with Mauritius in establishing a new marine protected area with clear and credible commitments to ensure the Chagos marine environment will be effectively protected for generations. This includes a full ban on commercial fishing, high-level IUCN-aligned protection for the Great Chagos Bank and only tightly controlled artisanal fishing to support any future Chagossian resettlement.

I know that there is great interest in the financial side. The Bill proposes that Parliament assumes a formal approval function for any future payments related to the Chagos Archipelago. This is not new ground. We have discussed many similar suggestions previously, as explained clearly by both my noble friend Lady Chapman and the Minister for the Overseas Territories in the other place. A requirement for a vote before payments is not only contrary to the principle that treaty payments can be made under the royal prerogative but would create an unacceptable risk for the long-term sustainability of the base. Without certainty, the UK and US military would not be able to invest in viable capabilities, which would have major operational implications for the base.

I turn finally to the Pelindaba treaty, raised by the noble Lord, Lord Murray. He asked whether the US could be prevented from having nuclear weapons on Diego Garcia. This is completely untrue and we are confident that nothing in this treaty conflicts with our abilities to uphold international law and to continue to operate the base as we do today.

I fully respect the strong views that noble Lords have on Diego Garcia and the future of the base. I hope that I have been able to answer most of the questions set out today. I have to say—I think this is not unexpected—that the Government cannot support the Bill because it seeks to tie their hands in protecting the base. It would subcontract the exercise of prerogative powers, which would set a dangerous precedent and be manifestly contrary to the national interest and security of the United Kingdom. I am afraid that we are not able to support the Bill, but I thank all noble Lords who have contributed to the debate today. I am sure we will continue to discuss this issue in future.