in 1966, the british government purchased the privately owned copra plantations and closed them. over the next five years, the british authorities forcibly and clandestinely removed the entire population of about 2,000 people, known as chagossians (or ilois), from diego garcia and two other chagos atolls, peros banhos and salomon islands, to mauritius. in 1971, the united kingdom and the united states signed a treaty, leasing the island of diego garcia to the us military for the purposes of building a large air and naval base on the island. the deal was important to the uk government, as the united states granted it a substantial discount on the purchase of polaris nuclear missiles in return for the use of the islands as a base. the strategic location of the island was also significant at the centre of the indian ocean, and to counter any soviet threat in the region.