Flag used by the British for Indian Ocean territory. Shutterstock

Britain is close to resolving its territorial dispute with Mauritius over the Chagos Archipelago, located in the central Indian Ocean.

For years, Mauritius has claimed the island group as part of its sovereign territory. It says that Britain unlawfully detached the islands from Mauritius in 1965, three years before Mauritius gained independence. The Mauritian position is backed by international courts and the United Nations, creating enormous pressure for Britain to decolonise.

London, however, has been reluctant to abandon the Chagos Archipelago. This is because the largest island, Diego Garcia, is the site of a strategically important US military base. Britain pledged to make Diego Garcia available to its American ally and has been anxious to avoid a situation where it is prevented from making good on these promises.

The US, for its part, has declined to become publicly involved in the dispute. Its private position is merely that the base on Diego Garcia should not be placed in jeopardy.

Read more: Britain’s ownership of the Chagos islands has no basis, Mauritius is right to claim them

In a deal announced in a joint statement, London and Port Louis have agreed that all but one of the Chagos Islands will be returned to Mauritian control as soon as a treaty can be finalised. This comes after nearly two years of intense negotiations. It seems as though settling the dispute was a top priority for Britian’s new Labour government.

Though the deal isn’t done yet, it is expected to go through. Both Britain and Mauritius, along with the White House, have endorsed the agreement, indicating that the toughest negotiations are complete.

Diego Garcia will remain under British administration for at least 99 years – this time with the blessing of Mauritius – enabling Britain to continue furnishing the US with unfettered access to its military base on the island.

In exchange for permission to continue on Diego Garcia, Britain will provide “a package of financial support” to Mauritius. The exact sums of money have not been disclosed but will include an annual payment from London to Port Louis. Both sides will cooperate on environmental conservation, issues relating to maritime security, and the welfare of the indigenous Chagossian people – including the limited resettlement of Chagossians onto the outer Chagos Islands under Mauritian supervision.

I’ve studied the Chagos Islands for 15 years, first as a master’s student and now as a professor. It often looked as though this day would never come.

The deal that’s been announced is a good one – a rare “win-win-win-win” moment in international relations, with all the relevant actors able to claim a meaningful victory: Britain, Mauritius, the US, and the Chagossians.

Win for Britain
Britain went into these negotiations with one goal in mind: to bring itself into alignment with international law.

London suffered humiliating setbacks at the permanent court of arbitration in 2015, concerning the legality of its Chagos marine protected area; at the International Court of Justice in 2019, when the World Court found that Mauritius was sovereign over the archipelago; and at the UN general assembly that same year, when a whopping 116 governments called on Britain to exit the Chagos Islands.

Mauritian sovereignty over the Chagos group had even begun to be inscribed into international case law.

London could probably have defied international opinion if it had wanted to. Nobody would have forced Britain to halt its illegal occupation of the Chagos Archipelago. But such a course would have badly undermined Britain’s global reputation and its ability to criticise others for breaches of international law.

This agreement will give Britain exactly what it wanted: a continued presence on Diego Garcia that conforms with international law.

Win for Mauritius
Mauritius, of course, went into these negotiations intent on securing full decolonisation at long last. Britain and the US now recognise that the Chagos Archipelago belongs to Mauritius.

Mauritius will not have day-to-day control of Diego Garcia, but it will be acknowledged as being sovereign there. The public description of the agreement also doesn’t seem to prohibit Mauritius from exercising its sovereignty over Diego Garcia as it relates to non-military domains.

Win for the US
The US is another clear winner from the deal. In fact, hardly anything will change for America. Washington will continue working closely with London, and will not need to negotiate an agreement with Mauritius on its rights to the base or the status of forces.

Indeed, Pentagon officials should be thrilled that their base on Diego Garcia has been put on firm legal footing. This is something that Britain alone was unable to offer. The bilateral agreement with Mauritius will ensure the security of the base for 99 years – no small feat.

Good for Chagos Islanders
Finally, the deal is good for the Chagos Islanders.

British agents forcibly depopulated the entire Chagos group between 1965 and 1973. The point was to rid the archipelago of its permanent population so that the US base on Diego Garcia would operate far from prying eyes. Britain deported the Chagossians to Mauritius and the Seychelles, which is where most Chagossians and their descendants still live. Some have migrated onwards, including to Britain.

Britain had long opposed the resettlement of the Chagos group by the exiled Chagossians. Mauritius, on the other hand, has indicated its openness to resettlement of the Outer Chagos Islands – so, not Diego Garcia – something that Port Louis is now free to pursue.

Not all islanders have welcomed news of an agreement. The Chagossians are a large and diverse group, with differing views about how their homeland should be governed. Some would have preferred Britain to administer the entire archipelago long into the future, feeling that Mauritius was an unwelcoming host to the exiled Chagossians. But Britain could not hold onto the Chagos Islands forever – at least, not lawfully.

For their part, the largest Chagossian organisations are content with the deal as it has been announced, and will now work with Mauritius on a resettlement plan.

The critics
This is the first instance of decolonisation that London has attempted since returning Hong Kong to China in 1997. Predictably, some in Britain are opposed to the settlement.

Some accuse the Keith Starmer government of “giving up” the Chagos Archipelago. But the islands were never Britain’s to give up – they were always Mauritian sovereign territory, and Britain was an unlawful occupier.

They are also wrong to blame this deal for jeopardising the base on Diego Garcia. The opposite is true: for better or worse, the agreement will resolve any uncertainty about the US base’s future. It will have total legal security.

Finally, critics are grasping at straws when they raise the prospect of Mauritius permitting a Chinese base in the Chagos Archipelago. This is a baseless smear. There is no indication whatsoever that Port Louis has any interest in hosting the Chinese military.

What happens now?
Britain and Mauritius still need to reveal the text of their bilateral treaty. But the deal is highly unlikely to fall through. Both governments, plus the White House, have welcomed the agreement – a sure sign that the hard work of negotiations is over.

All that remains is for the treaty to be ratified – a process that does not require a parliamentary vote in the House of Commons. There is no reason why this cannot be done quickly.

This could be the end of a shameful saga that went on for too long.