Chagos Archipelago sovereignty dispute

Sovereignty over the Chagos Archipelago is disputed between Mauritius and the United Kingdom. Mauritius has repeatedly asserted that the Chagos Archipelago is part of its territory and that the United Kingdom (UK) claim is a violation of United Nations resolutions banning the dismemberment of colonial territories before independence. The UK has stated that it has no doubt about its sovereignty over the Chagos, and has also said that the Chagos will be returned to Mauritius once the islands are no longer required for defence purposes. Given the absence of any progress with the UK, Mauritius has decided to "internationalise" the dispute and take up the matter at all appropriate legal and political forums. The African Union and the Non-Aligned Movement have expressed unanimous support for Mauritius on the Chagos issue.

The Constitution of Mauritius states that the Outer islands of Mauritius includes the islands of Mauritius, Rodrigues, Agaléga, Cargados Carajos and the Chagos Archipelago, including Diego Garcia and any other island comprised in the State of Mauritius. The Government of the Republic of Mauritius has stated that it does not recognise the British Indian Ocean Territory which the United Kingdom created by excising the Chagos Archipelago from the territory of Mauritius prior to its independence, and claims that the Chagos Archipelago including Diego Garcia forms an integral part of the territory of Mauritius under both Mauritian law and international law.

In 1965, the United Kingdom split the Chagos Archipelago away from Mauritius, and the islands of Aldabra, Farquhar, and Desroches from the Seychelles, to form the British Indian Ocean Territory. The islands were formally established as an overseas territory of the United Kingdom on 8 November 1965. However, with effect from 23 June 1976 Aldabra, Farquhar, and Desroches were returned to the Seychelles on their attaining independence.

...
Wikipedia