Britain creates the new Colony of BIOT

14 December 1960 - UN General Assembly Resolution 1514 (XV) “Declaration on the granting of independence to colonial countries and peoples”

The Resolution called for the speedy and unconditional end to colonialism in all its forms and manifestations and declared that “any attempt aimed at the partial or total disruption of the national unity and the territorial integrity of a country is incompatible with the purposes and principles of the Charter of the United Nations”. Notable among the nine states abstaining from voting was the UK. In a speech explaining its abstention, the UK representative spoke of “The degree to which the peoples of these territories, with our help, can succeed in creating new nations, undivided, strong and genuinely independent, is, we believe, crucial both to their own future happiness and to the progress and well-being of mankind as a whole”

July 1965 - Britain tells Mauritius it wants to detach Chagos

Notwithstanding these stated aspirations, in July 1965 the Governor of the British Colony of Mauritius was instructed to commence negotiations with Mauritian Ministers about detachment of the Chagos Archipelago from Mauritius. The proposal had its genesis in the late 1950s and early 1960s in the United States (US) as a result of the U.S. Navy identifying the island of Diego Garcia as a location for military facilities in the Indian Ocean. The US approached the British Government in 1963 about the use of Diego Garcia with the necessity for “detachment” in order to retain sovereignty and control and ensure the security of any future military base on the island. The US also made it clear that they would require areas of the newly created territory to be free of any inhabitants.

8 November 1965 - Britain Creates the British Indian Ocean Territory

On 8 November 1965, a prerogative Order in Council (UK Statutory Instrument No 1, 1965) created the new colony of the British Indian Ocean Territory (BIOT), comprising the Chagos Archipelago and some other islands formerly in the colony of Seychelles. On 16 December 1965, the UN condemned this act of detachment in Resolution 2066 (XX), calling on the UK to fully implement Resolution 1514 (XV) and “to take no action that would dismember the Territory of Mauritius and violate its territorial integrity”. The UK ignored this and pressed ahead with its plans for the BIOT assured by the support of the US. On 30 December 1966, the US and the UK governments signed an Exchange of Notes making the entire Chagos islands “available to meet the needs of both Governments for defense” .

Mauritian Independence 1968

Mauritius was granted independence by the British in 1968. British Cabinet papers at the time reveal that Harold Wilson, the Prime Minister, informed the Mauritian Premier in September 1965 that part of the price for independence was Mauritius’ assent to the detachment of the Chagos. In the immediate post-independence period, the excision of the Chagos was of limited consequence to the new state of Mauritius which was struggling with economic and ethnic problems and it was not until June 1980 that a majority of the Mauritian parliament first called on the UK to return Diego Garcia to Mauritius and the first formal claim was subsequently made by Mauritius on 9 October 1980 in an address by the Mauritian Prime Minister to the UN General Assembly.

Mauritius Claims Sovereignty 1982

In 1982, following the report of a select committee into what had happened in 1965, the Mauritian Government’s formal position was that Chagos had been illegally excised from Mauritian territory. Since then, Mauritius has repeatedly claimed sovereignty over the Chagos. Meanwhile, the UK has consistently maintained that it has no doubts about its claim to sovereignty whilst at the same time acknowledging that it will cede the islands to Mauritius when they are no longer required for defence purposes.

20 December 2010 - Mauritius challenges British Sovereignty in an UNCLOS Tribunal

On 20 December 2010 following the declaration of a Marine Protected Area (MPA) around Chagos by the United Kingdom, the Government of Mauritius initiated proceedings against the UK Government under UNCLOS to challenge its legality on the basis of the disputed sovereignty. Mauritius argued that the UK, not being a “coastal State” under UNCLOS and international law, had no authority to purport to establish a MPA around the Chagos Archipelago. The UK and Mauritius presented their arguments to the Tribunal in April 2014. Both parties agreed to the publication of their arguments which can be found on the website of the Permanent Court of Arbitration. The Tribunal ruled in 2015 that it did not have jurisdiction over issues of sovereignty but went on to declare that the MPA had been created in breach of UNCLOS.