The UK-Mauritius Chagos Treaty – the way ahead

It has taken 25 years to reach this point. Perhaps Mauritius’ 60th Independence Day celebration on 12 March 2028 will be the moment to mark the final implementation of this historic treaty

By David Snoxell

Since my article of 18 July ‘Chagos Agreement: A New Chapter for UK-Mauritius Relations’ there have been several developments concerning the process towards ratification of the treaty which was signed by both prime ministers on 22 May. The British Government introduced primary legislation in Parliament on 15 July to enable the Agreement to be implemented. This is the Diego Garcia Military Base and British Indian Ocean Territory Bill. As Parliament went into recess on 22 July and resumes on 1 Sept, debate on the Bill will begin next week.

UK-Mauritius Treaty. Pic – YouTube

The signed treaty was laid before Parliament on 22 May and thoroughly scrutinised in debates in both Houses. The scrutiny period ended on 3 July. Neither House objected to the government proceeding to ratify the treaty.

The purpose of the Bill is to enable the Agreement to be implemented. It consists of four main provisions that address the legal and administrative changes required:

– Administration of Diego Garcia: The Bill ensures the UK’s ongoing administration of Diego Garcia.
– Legislative Powers: It grants delegated powers to create new legislation as required by the Treaty.
– Nationality and Territory Status: It amends the British Nationality Act to reflect that the BIOT will no longer be a British Overseas Territory, while also protecting the nationality rights of those born in the Chagos Archipelago and their descendants.
– Sovereignty and Authority: It formally recognizes Mauritian sovereignty over the Chagos Archipelago while providing for the UK to retain rights and authority over Diego Garcia, which are necessary for the long-term, secure, and effective operation of the military base.

Once the Bill has been passed by both Houses and Royal Assent granted, sometimes on the same day, the treaty comes into force and will be ratified. It may take about 6 months. The Mauritian process of ratification is simpler and is expected to be ready at the same time. When both parties have ratified, the treaty becomes international law and is registered with the UN. Given the engagement and five resolutions adopted by the UN General Assembly from 1964 to 2019 concerning Chagos, I would expect the UK and Mauritius to sponsor a joint resolution at the 2026 UNGA endorsing the treaty. The process of transferring the Islands and replacing the UK Marine Protected Area with a Mauritian MPA will then begin. It could take 2 to 3 years for transition to be completed and resettlement to start.

Not everything will be plain sailing. Those against the treaty in the media, academic bodies and Parliament may continue to look for ways of slowing down or opposing the legislation. For example, the 1996 Pelindaba Treaty establishing Africa as a nuclear-weapon-free-zone to which most African states, including Mauritius are parties, has recently been raised in the press as a potential obstacle to the UK/Mauritius Treaty. This has, however, been implicitly addressed at Article 7(3) of the treaty. It will thus be for Mauritius to deal with, should there be suggestions of incompatibility from other parties to the Pelindaba Treaty. It should be noted that the participating states consider that the zone encompasses the Chagos Archipelago including Diego Garcia.

But there are many who support the treaty, including most UN member states. There has been an avalanche of press reporting following the Pope’s meeting at the Vatican with Olivier Bancoult and the Chagos Refugees Group on 23 August.

Pope Leogave his blessing to the outcome and told the Chagossians that he was “delighted” that the treaty had been reached, saying it represented a “significant victory” in their long battle to “repair a grave injustice”. He added: “The renewed prospect of your return to your native archipelago is an encouraging sign and has symbolic force on the international scene.” Being an American, the Pope’s moral support carries extra weight with President Trump and his advisers. His predecessor Pope Francis made a similar appeal when he visited Mauritius in September 2019.

But while the Treaty is a major step forward for both the UK and Mauritius and the rule of law, it is by no means a resolution for Chagossians who remain ‘banned’ from resettling on the largest island, Diego Garcia, except for occasional escorted visits controlled by the UK. About 40% of the population lived on this island and any prospect of return for those still alive and their descendantshas been dashed once again.

This injustice undermines the full implementation of international law and human rights that the treaty implies. Chagossians may justly feel that they have been excluded in favour of US and UK defence and security priorities. It is to be hoped that this omission will be rectified over time after confidence building visits by Chagossians to Diego Garcia have taken place. I would expect the UNGA and the Chagos Islands All-Party Parliamentary Group to continue to advocate the interests of Chagossians. The APPG was represented on the visit to the Pope by its legal adviser Richard Gifford.

As with all treaties, this one has been achieved through diplomatic compromise. A strong and positive UK/Mauritius bilateral relationship and partnership will underpin a smooth transition. It has taken 25 years to reach this point. Perhaps Mauritius’ 60th Independence Day celebration on 12 March 2028 will be the moment to mark the final implementation of this historic treaty enabling a just and lawful resolution to both the sovereignty dispute and the exile of Chagossians from their Islands.

David Snoxell has been Coordinator of the Chagos Islands (BIOT) APPG since 2008. He was British High Commissioner to Mauritius, 2000-04.

Mauritius Times ePaper Friday 5 September 2025