Diego Garcia Military Base and British Indian Ocean Territory Bill

Lord De Mauley Excerpts

2nd reading
Tuesday 4th November 2025 Lords Chamber

[Lord De Mauley (Con)]

My Lords, the International Relations and Defence Committee, which I have the honour to chair, decided, on the announcement of the deal with Mauritius, to have a look at the proposed handover of sovereignty of the British Indian Ocean Territory. As a result, the committee raised a number of issues. In view of the fact that we are a cross-party committee, we did not get into an argument about the Government’s detailed reasons for doing the deal. We simply observed that the decision to proceed was ultimately political. That statement itself acknowledges the fact that several members of the committee, including me, were very doubtful about the Government’s stated legal and other reasons. My noble friend Lord Lilley eloquently set out the basis for some of those doubts.

Our witnesses were unanimous in their view that Diego Garcia holds a pivotal strategic role for the United Kingdom and the United States, and that it is critical for broader western security strategy in the Indo-Pacific—on that much at least, we can agree with the Government. The Government argue that the deal secures Diego Garcia as a UK base. As an article from RUSI issued since our inquiry points out, however, the base was already secure prior to the ceding of sovereignty. We heard arguments that I find persuasive that the deal could, in fact, make the base less secure in absolute terms. I will come to some of those in a moment.

The committee focused on four key areas: the future of defence and security arrangements on Diego Garcia; the rights of the Chagossian people; the environmental protection of the archipelago; and the costs arising from the agreement.

As regards defence and security, witnesses alerted us to a number of potential risks. Most of these revolved around increased vulnerability to Chinese political warfare tactics. Our attention was drawn to the fact that there remains a risk, particularly in the context of expanding Chinese influence on the African continent, that the base may need to be used in a way that is perceived as contentious in Africa—for example, arising from the African Nuclear-Weapon-Free Zone Treaty—and could cause diplomatic difficulties, to say the least, for the UK in the future.

As regards the long term, we heard evidence that the Government’s confidence in the strength of the UK’s right of first refusal to an extension after 99 years was unconvincing. This was because, among other things, it lacks the mechanism for enforcement and would be difficult to assert in practice. This is a significant potential source of future vulnerability that the Government must address now as part of their long-term strategic planning.

Being in Hong Kong at the time of its handover to the Chinese in 1997—and look what a success that has been—brought home to me that 99 years today is little more than a single lifespan. We noted that the agreement has introduced a risk that Mauritius—as the sovereign power, if the treaty is ratified—could object to a specific military operation from Diego Garcia, due to differing views on whether it meets the requirements of international humanitarian law. While the Government were categorical that this would not limit UK-US freedom of action, we were warned that such objections could lead to lawfare and create diplomatic difficulties for the UK, bringing the risk that they affect military operations.

I turn to the rights of Chagossians. We met a cross- section of members of the community in UK and Mauritius. While we acknowledge that their views cannot be representative of the entire community, those we met expressed unanimous dissatisfaction with the consultation processes conducted by both the UK and Mauritian Governments. Concerns revolved principally around, first, the vague language relating to resettlement and, secondly, the inadequacy of arrangements to ensure that Chagossians benefit from the financial package being given to Mauritius by the UK. It is notable that under Article 10 of the agreement, the UK is required to give preference to suitably qualified Mauritian nationals, to the maximum extent practical when employing contractors, but no reference is made to prioritising employment for those of Chagossian heritage.

To date, the Government have not provided a clear or convincing rationale for excluding Chagossians from employment on Diego Garcia. The lack of attention to the interests of Chagossians is even more stark in the context of the financial package. Concerns were raised to us about the £40 million trust fund that the UK will set up under Article 11 of the agreement, dedicated to the Chagossian community, with Mauritius establishing the fund under its financial regulations, in consultation with the UK.

A key theme during our discussion with the Chagossians was the lack of clarity on how the trust fund would be managed, with participants highlighting the Mauritian Government’s poor record in supporting their community. For example, in 2016 the UK provided £40 million to the Mauritian authorities to improve Chagossian lives, yet only £1.3 million was disbursed, and even those funds came with restrictive conditions. Given this, it is surprising that the Government have surrendered the right to manage this fund to Mauritius, when the UK is itself well equipped to manage funds on behalf of others.

The Government have committed to providing a factual update to Parliament on the modalities of the trust fund, and on eligibility for resettlement. I ask the Minister when that update will be forthcoming. Alongside the trust fund, a £45 million annual development grant will be provided by the UK for a period of 25 years, to support development projects aimed at improving the economic welfare of Mauritius and its citizens. Why has a proportion of the grant, at least, not been earmarked for the benefit of Chagossians? I find it extraordinary that it was a Labour Government, in the 1960s, who evicted the population of the Chagos Islands callously from their island homes, and it is a Labour Government, in 2025, who have so blatantly failed to give adequate attention to the rights of the Chagossians.

I turn to the environmental implications. The committee heard the archipelago described by a credible environmental expert as

“the most important reef wilderness on the planet”.

Concern arises partly because there is uncertainty about the future of the marine protected area established around the BIOT in 2010 by the UK, as the noble Lord, Lord Thurlow, said, given that it has not been recognised by Mauritius. We were told in particular that the Mauritian Government’s track record in marine governance is poor. Furthermore, assuming that Mauritius acts in good faith in the matter of the environment, its enforcement capabilities are currently limited, as again the noble Lord, Lord Thurlow, said, to just two ocean-going vessels and two aircraft that are incapable of reaching Chagos directly.

I turn finally to the cost of the agreement. For each of the first three years, the UK will pay Mauritius £165 million. It will then pay £120 million per year for the following 10 years. Thereafter, it will continue to pay the equivalent of £120 million annually, increasing in line with inflation. In addition, the UK will fund the £40 million trust fund and the £45 million annual development grant that I referred to earlier. The Government calculate the total cost of all this at approximately £3.4 billion. However, critics have questioned the methodology used and argued that the total cost of the agreement could be very considerably greater.

Attempting to justify the cost of the agreement, the Minister asserted to us that the payments to Mauritius compare favourably with payments made by others for overseas bases. For example, he indicated that France had recently arranged an €85 million per year deal with Djibouti on its basing arrangements for a military base 15 times smaller than Diego Garcia. We noted, however, that the Government’s emphasis on the size of the Djibouti base draws a false equivalence between size and cost; it therefore calls into doubt any such comparison. We called on the Government to provide the committee with further information on how the overall leasing costs for Diego Garcia were determined and how these may affect the allocations in the defence budget. No such data has yet been produced.

As I hope I have outlined, the Government still have some very serious questions to answer on the future defence and security arrangements, the rights of the Chagossians, the environmental protection of the archipelago, and the costs arising from the arrangement.