It is a landmark agreement on what many call the last British colony in Africa. Chagos is an archipelago of 60 islands and atolls known as the British Indian Ocean Territory. The United Kingdom and the United States have a military base on Diego Garcia atoll that serves as a base for missions in the Middle East.

Chagos was conquered by the Portuguese and became part of Mauritius when it became a French colony. In 1814 the islands passed into British hands by the Treaty of Paris, which ended the war with Napoleon. In 1968, they gained independence from the United Kingdom at the polls, but the British kept Chagos. A legal battle ensued, in which they also claimed the mass expulsion of its inhabitants.

In 2019, the Hague Court ruled in favour of Mauritius . But the then Boris Johnson government refused to hand them over because it is a key area in the dispute with China. Finally, British Prime Minister Keir Starmer has reached an agreement with his Mauritian counterpart to hand them over and finance their repopulation and investment in infrastructure , in exchange for maintaining the military base in Diego Garcia with Joe Biden's blessing.

The Chagos case is similar to that of the Malvinas and some experts point out that it sets a precedent for Argentina's claim.