U.K.’s Chagos Islands deal with Mauritius risk entrenching exile of some islanders

Context

• In 2024, the UK agreed to transfer sovereignty of the Chagos Islands to Mauritius while retaining control of the military base on Diego Garcia under a 99-year lease.

• This followed the 2019 International Court of Justice (ICJ) ruling supporting Mauritius’ sovereignty claims.

• The base, which plays a central role in UK-US defence operations in the Indian Ocean, will now be leased from Mauritius under a new 99-year lease.

• Under the deal, the UK will pay Mauritius an average of £101 million ($129m) per year — amounting to a total of £3.4 billion ($4.35 billion) over the course of the lease.

• The US, which co-operates the Diego Garcia base with the UK, will shoulder the base’s operational costs — which Starmer said exceed the UK’s financial contribution. Former US President Donald Trump has publicly welcomed the deal.

Mapping

• Location: It is situated 500 km south of the Maldives in the Indian Ocean, and consists of 58 islands.

• History: It was inhabited in the late 18th century when the French brought enslaved African and Indian laborers to work on coconut plantations.

• Under the 1814 Treaty of Paris, France ceded the Chagos Archipelago, along with Mauritius, to Britain, marking the beginning of British control over the region.

• In 1965, Britain detached the Chagos Islands from Mauritius to create the British Indian Ocean Territory (BIOT), compensating Mauritius with a 3 million-pound grant.

• Despite Mauritius gaining independence in 1968, the Chagos Archipelago remained under British control.

Diego Garcia

• It is coral atoll and the largest island of the Chagos Archipelago, located 7 degree south of the equator. It became a military base for the US and UK in 1986.

• Diego Garcia has played a pivotal role in military operations, including US-UK strikes on Houthi targets in Yemen (2024 2025), humanitarian missions to Gaza, and earlier, bombing campaigns against the Taliban and al-Qaeda in Afghanistan in 2001