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Disputes over the British Indian Ocean Territory: December 2016 update

Published Thursday, December 1, 2016

This briefing describes the main developments since mid-2013 in long-running disputes over the British Indian Ocean Territory (BIOT). In November 2016 the UK Government decided not to allow Chagossian resettlement. The status of the Marine Protected Area is contested. The UK and Mauritius are holding talks on sovereignty. Mauritius says it may seek an advisory opinion from the International Court of Justice. The US military base on Diego Garcia is set to continue until 2036. Meanwhile, there continues to be litigation in the English courts.

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Between 1968 and 1973 the British Government cleared the entire Chagos Archipelago of its inhabitants, in anticipation of a US military base on the biggest island, Diego Garcia. The Archipelago was made a colony, the British Indian Ocean Territory (BIOT). It subsequently became a British overseas territory.

Two main disputes have arisen from these events. One has been between the Chagos Islanders and the British Government over the legality of their removal and whether they have a right to return. The other has been between the UK and Mauritius about sovereignty over the BIOT. In 1965 the UK undertook that it will cede sovereignty to Mauritius once the BIOT is no longer required for defence purposes.

A May 2013 Library briefing surveyed the origins and subsequent evolution since 1965 of these disputes, including past and ongoing legal cases brought before British, European and international courts. The briefing went on to explore potential ways forward for resolving these disputes by the time of the UK general election in May 2015.

This update summarises the main developments over the intervening three years.

A fresh resettlement feasibility study has been carried out for the British Government. It set out three resettlement options: large-scale resettlement; medium-scale resettlement; and pilot, small-scale resettlement. In 2015 it conducted a consultation exercise with Chagossians and other interested parties. However, on 16 November 2016 the Government announced that it had decided not to allow resettlement. The decision provoked condemnation from Mauritius and supporters of the Chagossian cause in the UK, and raises the prospect of further legal action.

A Marine Protected Area (MPA) introduced by the British Government around the Chagos Archipelago (apart from Diego Garcia, where there is a US military base) in 2010 was ruled unlawful in 2015 by a Tribunal under the UN Convention on the Law of the Sea. The British Government insists that the MPA is still in place. The Tribunal was much more equivocal on sovereignty than the Mauritian Government, which brought the case, will have hoped. It declined jurisdiction on the issue but found that the UK’s 1965 undertaking to cede sovereignty to Mauritius when the BIOT is no longer required for defence purposes is binding under international law.

In July 2016 Mauritius said that it would seek a referral by the UN General Assembly to the International Court of Justice later in the year in order to obtain an advisory opinion on sovereignty. Mauritius eventually refrained from seeking a referral and there have been talks between the two governments. But doing so in 2017 remains possible.

A decision on whether to extend the life of the US military base on Diego Garcia for a further 20 years had to be made by the end of 2016. On 16 November 2016, the British Government announced that this decision had now been taken.

In June 2015 the Supreme Court heard an application for the 2008 verdict of the House of Lords – which ruled that the use in 2004 of Orders in Council to prevent the Chagossians from returning had been lawful – to be set aside. In June 2016 the Supreme Court ruled against the application by a majority of 3 to 2. However, now that the Government has decided against allowing resettlement, the judgment may open the way to an application for judicial review of the original ban.

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