Ilois (also known as Chagossians) are a group of Creole-speaking people, mostly of Indian descent (also notably from Madagascar, Mauritius, and Mozambique), which dwelled on the Chagos Archipelago for a certain period of time, most having arrived as fisherman, farmers, and coconut plantations workers during the 19th century (some claim that the very first Ilois were brought to the Archipelago as slaves by the French on 1776). The Ilois, numbering some 2000 people at the time, were expelled by the British Government between 1967 and 1973, first to the island of Peros Banhos, 100 miles away from their homeland, and then, in 1973, to Mauritius and the Seychelles (for the relationship between the Chagos Archipelago and Mauritius, see Chagos Archipelago). Their expulsion was purportedly due to the establishment of a joint US-UK naval base of Diego Garcia (the American lease on which is due to expire on 2016), under the pretext that their small islands could not support both the naval base and the civilian population.

In 1983, the UK gave the Mauritian government £4m, of which the Mauritian government transferred £1m to those deported Chagossians dwelling in its realm. Later, some 30 years after their deportation, the Ilois demanded the right to return to their homeland. Their case was brought to the High Court of Justice in London by a British firm of solicitors, Sheridans, and on November 3 2000 the High Court ruled in their favor, stipulating that they should be allowed to return to their homeland. From November 5 to 23, 2001 , over two hundred Chagossians maintained a vigil outside the British High Commission in Port Louis, Mauritius. On 21 May, 2002, the British Foreign Affairs Secretary Jack Straw signed a document conferring British citizenship upon the Ilois, later implemented in "Section 6: The Ilois: Citizenship" of the British Overseas Territories Act 2002. On October 9, 2003, the High Court, questioning the validity of its previous ruling, decreed that the Ilois were not entitled to compensation from the British Government.