Chagos Islanders expelled decades ago from their homes on the Indian Ocean archipelago by the UK have taken their case to the supreme court.



Opening a fresh legal challenge to restore the rights of the exiled islanders, Nigel Pleming QC said that a United Nations vote last week signalled a significant shift in international opinion on the dispute and that there was increasing pressure on the UK to allow native Chagossians to return to their homes.



Britain expelled the entire population of the Chagos Islands more than 40 years ago to make way for a US military base on the island of Diego Garcia.

The Chagossians are seeking a ruling that a decision to create a marine park around the British-controlled islands was for the improper purpose of preventing their future resettlement.

Lawyers for the deported 1,500 Chagossians claim that the reason the last Labour government set up a marine protected area around the archipelago was purely for the improper purpose of preventing resettlement.

Olivier Bancoult, the Chagossians’ leader, has been fighting in the courts on behalf of the islanders for decades.



In the latest challenge, Bancoult is seeking to overturn a court of appeal ruling that there was no improper motive behind the marine park designation, which includes a ban on fishing – a crucial issue if the islands are to be resettled.

The Chagossian legal challenge also argues that imposing a marine protected area on the remote archipelago does not require a complete ban on all fishing rights.

The Foreign Office refers to the islands as British Indian Ocean Territory (BIOT). Neighbouring Mauritius claims the islands were illegally cut out of its territory prior to independence. Diego Garcia was used for rendition flights in the aftermath of the 9/11 attacks on New York and Washington.



Last week the UN general assembly voted by an overwhelming majority to refer the legal status of BIOT to the international court of justice in The Hague for an advisory opinion.



“The international pressure is increasing,” Pleming told the seven supreme court justices hearing the case. “It’s not going away.”



The exiled Chagossians, who live mainly in Mauritius and the UK were “hopeful and optimistic that their right of abode will be returned”, Pleming said. “There are reasonable prospects that [they] will one day be resettled.”



For years until 2010, Chagossians living in Mauritius had continued fishing around BIOT under licence. The ban on their hook and line fishing had taken away their livelihoods, Pleming told the court.



The justices will hear two days of legal argument about fishing rights and the way in which the Foreign Office imposed the marine protectied areas. They are expected to reserve judgment.



At the start of the case, Lord Neuberger informed the court that the recently retired justice Lord Toulson had died following an operation.



Toulson retired from the UK’s highest court last year. He made “a major contribution to the law of this country”, Neuberger said.