After decades of international legal battles, Britain has finally signed an agreement to hand over the Chagos Islands, home to the US/UK naval and bomber base of Diego Garcia in the Indian Ocean, to Mauritius. The UK government will lease back the base from Mauritius at a cost of £101 million a year for an initial period of 99 years.

Announcing the deal at the Northwood military base, near London, Prime Minister Sir Keir Starmer said the base was crucial for British counter-terrorism and intelligence and is “right at the foundation of our safety and security at home.” He added, without explanation, “By agreeing to this deal now on our terms, we’re securing strong protections, including from malign influence, that will allow the base to operate well into the next century, helping to keep us safe for generations to come”.

Britain separated the Chagos Islands from Mauritius in 1965 before it became independent in 1968 and incorporated them into the specially created British Indian Ocean Territories (BIOT), violating 1960 UN resolution 1514 banning the breakup of colonies before independence. In one of its most shameful episodes of post-war colonialism, it forcibly evicted up 2,000 islanders from their homes in the late 1960s to early 1970s, deporting them to Mauritius and the Seychelles, another former British colony. A leaked internal Foreign Office memo notoriously belittled the Chagossians as “a few Tarzans and Man Fridays”.

This was done to make way for the leasing of Diego Garcia, the largest island in the 50-island archipelago, to the US Naval Support Facility. Britain’s purpose in granting Washington the initial 50-year lease on Diego Garcia—kept secret from both Parliament and the US Congress—was to secure an $11 million discount on the US-made Polaris nuclear weapons system, which the Labour Party had pledged to scrap when in opposition.

The Islands occupy a strategically placed location in the Indian Ocean, halfway between India and East Africa. By the late 1980s, Diego Garcia, which hosts between two and five thousand US military personnel, had become one of the leading overseas military bases of the US and the main base available to Britain in the area. US imperialism has used Diego Garcia to support its criminal operations from Vietnam to Iraq and Afghanistan. It has facilities to accommodate nuclear submarines, aircraft carriers and large airplanes, plays a key role in US intelligence-gathering and serves as a surveillance centre for the Middle East, as well as providing a “dark site” where the CIA detained and tortured people and refuelled extraordinary rendition flights.

Britain’s decision to surrender sovereignty over the Chagos Islands comes six years after the International Court of Justice (ICJ) issued an advisory opinion in 2019 noting that “the process of decolonization of Mauritius was not lawfully completed” and that the UK had violated United Nations resolutions prohibiting the breaking up of colonies before granting independence. With its customary imperial arrogance, the British government ignored this and similar rulings.

But there was another much more important opinion issued by the United Nations International Tribunal for the Law of the Sea (ITLOS) that the British government could not ignore, despite its protestations at the time. ITLOS had ruled that the UK had no sovereignty over the Chagos Islands and thus it considered all the seas and therefore airspace around the Chagos islands as belonging to Mauritius.

Although the 2021 ruling was, like the ICJ’s, only advisory, the maritime court—a court that affects international trade—can make its opinions binding in law. It would mean that Mauritius could take legal action against Washington and London or any company supplying their operations for invading its air or sea space if they had done so without permission from Mauritius. Furthermore, Mauritius would be entitled to open up the Islands to Chinese or Russian bases.

This was a risk the US and UK governments were not prepared to take. Starmer said, “We had to act now because the base was under threat”, adding that Mauritius would have taken Britain to court within weeks and the UK had no “realistic prospect of success.”

The deal sets a 24-mile exclusion zone around Diego Garcia, where nothing can be built without UK consent. Foreign military and civilian forces will be banned from the other islands in the archipelago, with the UK retaining power to veto access to the islands, provisions aimed at China. Under the terms of the deal the UK must notify Mauritius if it plans to use Diego Garcia to launch an “armed attack on any third state” and give Mauritian companies priority when awarding contracts related to the maintenance of the base.

The UK will pay Mauritius £101 million a year, with the rent set to rise with inflation, for 99 years, at which point the lease can be renewed for up to 40 years if both sides agree. Starmer sought to justify the cost as “value for money”, even as his government plans £5 billion in welfare cuts, because it is “slightly less than the running cost of an aircraft carrier minus the aircraft”.

Starmer said the UK’s four partners in the “Five Eyes” security alliance—the US, Canada, New Zealand and Australia—backed the agreement, while Russia, China and Iran opposed it. US President Donald Trump had backed the deal when he met Starmer in the White House in February, saying “I have a feeling it’s going to work out very well”. Secretary of State Marco Rubio welcomed the deal, saying it “secures the long-term, stable and effective operation of the joint US-UK military facility at Diego Garcia, which is critical to regional and global security.”

Mauritius Prime Minister Navin Ramgoolam hailed the deal as a “great victory for the Mauritian nation”. He added, “I have always said we must obtain our sovereignty over the totality of the Chagos, including Diego Garcia”, adding that it symbolised the completion of “the total process of decolonisation”.

The deal rides roughshod over the claims of the 1,344 Chagossian islanders who were forcibly displaced from Diego Garcia. They have been denied the right to return to their homes, which international lawyer Professor Philippe Sands QC, said was arguably “a crime against humanity within the meaning of Article 7 of the [International Criminal Court] Statute.” Under the terms of the agreement, to be ratified by parliaments in London and Port Louis, Mauritius is “free to implement a programme of resettlement” on the islands, excluding Diego Garcia. But it does not require the residents to be resettled. The deal establishes a trust fund to benefit the Chagossians.

For more than five decades, Britain carried out one crime after another against the Chagossians while lying, ignoring court decisions, invoking Royal Prerogative and then covering up its actions. The islanders have lived in impoverished conditions ever since, with just a few allowed into Britain.

None of the promises of support and compensation were kept. Many of the islanders were simply abandoned when they landed. The islanders, as a condition of accepting Britain’s derisory offer of compensation in the 1980s, which largely failed to materialise, were required to renounce their right to return. In 2016, the British Foreign Office set up a £40 million fund to compensate the islanders. Five years later, after it had distributed just £12,000 in direct support to them, Croydon Council, tasked with assessing how to allocate the money, abandoned the work.

The displaced islanders, having fought unsuccessfully in UK courts for years for the right to go home, brought an 11th-hour legal challenge to try to stop the UK transferring sovereignty of the Chagos Islands to Mauritius to enable their case for their right of return to their homeland to be settled. Later that day, another judge discharged the injunction, enabling the agreement to hand over the Islands to go ahead.

The two British Chagossians Bertrice Pompe, 54, and Bernadette Dugasse, 68, both born on Diego Garcia, who brought the injunction, accused the British government of betrayal. They have vowed to keep fighting to try to realise their dream of returning to their place of birth. Pompe said, “We’ve been ignored, we’ve been invisible, we don’t exist. They don’t even mention us. When they expelled us, everything was hidden [as if] there were no human beings on the island, just some Man Fridays. And they’re not saying it [now], they’re not pronouncing the words, but by their actions they’re doing the same thing. We’re being scammed over and over again.”

Jemmy Simon, from the Chagossian Voices group, told the BBC that there was “nothing in there [the deal] that is any good for us”. “I’m beyond horrified and angry right now.” “They [the British government] promised to look out for our best interests—absolute rubbish”, she said, adding “It is up to Mauritius to decide if we will get to resettle on the outer islands or not, but they don’t have to if they don’t want to”.