Separation of the Chagos Archipelago

• Jurisdiction: Derecho Internacional
• Judge: Gaja,Sebutinde,Iwasawa,Bennouna,Cançado Trindade,Robinson,Bhandari,Gevorgian,Tomka,Donoghue,Salam,Xue,Yusuf,Abraham
• Date: 25 February 2019
• Court: International Court of Justice

(Advisory Opinion)

International Court of Justice.

(Yusuf, President; Xue, Vice-President; Tomka, Abraham, Bennouna, Cançado Trindade, Donoghue, Gaja, Sebutinde, Bhandari, Robinson, Gevorgian, Salam and Iwasawa, Judges)

Legal Consequences of the Separation of the Chagos Archipelago from Mauritius in 1965 1

International Court of Justice — Advisory jurisdiction — Article 65(1) of Statute of Court — Competence of General Assembly — United Nations Charter, 1945, Article 96(1) — Whether question submitted to Court of legal character — Alleged lack of clarity of terms of request — Whether having effect on legal nature of question — Whether depriving Court of jurisdiction

International Court of Justice — Advisory jurisdiction — Discretion to decline to give opinion — Requirement of compelling reasons for Court to decline to give opinion — Whether questions raising complex and disputed factual issues unsuitable for determination — Whether Court having sufficient information and evidence — Requesting organ to determine whether opinion required — Whether advisory opinion would reopen findings of Arbitral Tribunal — Res judicata — Relevance of United Kingdom lack of consent to judicial settlement — Principle of consent to judicial settlement of disputes — Whether Court would be deciding a bilateral dispute

States — Decolonization — Independence — Separation of the Chagos Archipelago from Mauritius — Whether process of decolonization of Mauritius lawfully completed — Relevant period — Applicable law — Right of self-determination — Whether selfdetermination customary law during relevant period — Territorial integrity — Whether detachment of Chagos Archipelago unlawful

International organizations — United Nations — General Assembly — Decolonization — Functions of the General Assembly regarding decolonization — Non-self-governing territories — Free and genuine will of people of a non-self-governing territory — Mauritius

Human rights — Self-determination — United Nations Charter, 1945 — General Assembly Resolution 1514 (XV) 1960 — Right erga omnes — Chagos Archipelago — Mauritius — Continued administration of Chagos Archipelago by United Kingdom — Consequences under international law arising from continued administration by United Kingdom of Chagos Archipelago — Whether continued administration constituting a wrongful act — Whether responsibility of United Kingdom engaged under international law — Whether United Kingdom obliged to put an end to any internationally wrongful act — Obligations upon all States under United Nations Charter and international law

Summary:2The facts:—On 22 June 2017, the General Assembly of the United Nations adopted resolution 71/292, by which it requested the International Court of Justice (“the Court”) to give an advisory opinion on the following questions:

• (a) Was the process of decolonization of Mauritius lawfully completed when Mauritius was granted independence in 1968, following the separation of the Chagos Archipelago from Mauritius and having regard to international law, including obligations reflected in General Assembly resolutions 1514 (XV) of 14 December 1960, 2066 (XX) of 16 December 1965, 2232 (XXI) of 20 December 1966 and 2357 (XXII) of 19 December 1967?

• (b) What are the consequences under international law, including obligations reflected in the above-mentioned resolutions, arising from the continued administration by the United Kingdom of Great Britain and Northern Ireland of the Chagos Archipelago, including with respect to the inability of Mauritius to implement a programme for the resettlement on the Chagos Archipelago of its nationals, in particular those of Chagossian origin?3

The Chagos Archipelago is a group of islands and atolls in the Indian Ocean which, between 1814 and 1965, was administered by the United Kingdom as a dependency of the colony of Mauritius. On 14 December 1960, the General Assembly of the United Nations adopted Resolution 1514 (XV) entitled “Declaration on the Granting of Independence to Colonial Countries and Peoples” (“Resolution 1514 (XV)”).

In 1964, during talks between the United States of America and the United Kingdom, the United States of America expressed interest in establishing a military base on Diego Garcia, the largest island in the Chagos Archipelago. The talks resulted in a 1966 agreement between the United Kingdom and the United States on the availability for defence purposes of the British Indian Ocean Territory (“BIOT”) (“the 1966 agreement”).4

The United Kingdom began talks with representatives of Mauritius concerning the independence of the colony, which culminated in the “Lancaster House agreement” of September 1965. That agreement provided for the independence of Mauritius but also for the detachment of the Chagos Archipelago from Mauritius on certain conditions.5 In November 1965, the United Kingdom established a new colony, the British Indian Ocean Territory (“BIOT”), comprising the Chagos Archipelago along with the Aldabra, Farquahar and Desroches Islands, which had been detached from the Seychelles but which were later returned. In March 1968, Mauritius acceded to independence.

From 1967 to 1973, the United Kingdom forcibly removed or prevented from returning the entire population of the Chagos Archipelago (“the Chagossians”). The Chagossians became dispersed across several countries, including Mauritius, the Seychelles and the United Kingdom. The United Kingdom subsequently, on several occasions, decided against allowing the Chagossians to resettle on the archipelago. From 1998 to 2018, a series of unsuccessful challenges were brought by a Chagossian in the domestic courts of the United Kingdom and in the European Court of Human Rights, seeking to allow the Chagossians to return.6

Held:—A. The jurisdiction of the Court to provide an Advisory Opinion (unanimously): The Court had jurisdiction to give the advisory opinion requested. The power of the Court to give an advisory opinion was based upon Article 65(1) of its Statute.7 The General Assembly was an organ duly authorized to request an advisory opinion by Article 96(1) of the Charter of the United Nations.8 The two questions asked were legal in character, as they required the Court to examine a situation by reference to international law. Lack of clarity in the drafting of a question did not deprive the Court of jurisdiction (paras. 55–62).

B. The Court's discretion whether or not to give an Advisory Opinion (by twelve votes to two, Judges Tomka and Donoghue dissenting): There were no compelling reasons for the Court to exercise its discretion not to give an Opinion (para. 91).

(1) The Court had a discretionary power to decline to give an advisory opinion, which existed to protect the integrity of the judicial function of the Court. However, the Court's answer to a request for an advisory opinion represented its participation in the activities of the United Nations, and should be refused only for compelling reasons (paras. 63–5).

(2) There was no compelling reason for the Court to decline jurisdiction on the ground that the questions raised complex and disputed factual issues

not suitable for determination in advisory proceedings. The Court had sufficient information on the facts before it to give the opinion requested, including a dossier from the United Nations, written statements of thirty-one States and the African Union, and official records from the United Kingdom regarding the detachment of the Chagos Archipelago and the independence of Mauritius (paras. 69–74).

(3) The Court could not decline to answer the question on the ground that its opinion would not assist the General Assembly in the performance of its functions. It was for the requesting organ, rather than the Court, to determine whether it required the opinion for the proper performance of its functions. The Court could not substitute its own assessment of the usefulness of the opinion requested for that of the General Assembly (paras. 75–8).

(4) The argument that an advisory opinion by the Court would reopen the findings of the Arbitral Tribunal constituted under the United Nations Convention on the Law of the Sea, Annex VIL,9 did not provide a compelling reason for the Court to decline the request. The advisory opinion was given to the organ entitled to request it, not to States. The principle of res judicata did not prevent the Court from giving an advisory opinion. The issues determined by the Arbitral Tribunal were not the same as those before the Court in the present case (paras. 40–50 and 79–82).

(5) To give the opinion would not be to circumvent the principle of State consent to the judicial settlement of disputes. The General Assembly sought the opinion so that it could be guided in discharging its functions relating to the decolonization of Mauritius. The matter of decolonization was of particular concern to the United Nations. The issues raised by the request were located in, and inseparable from, the broader frame of reference of decolonization. Divergent views on legal issues were usual in advisory proceedings, and that the Court had to pronounce on such issues did not mean that the Court by replying to the request was dealing with a bilateral dispute (paras. 83–90).

C. Whether the process of decolonization of Mauritius was lawfully completed having regard to international law (by thirteen votes to one, Judge Donoghue dissenting): The process of decolonization of Mauritius was not lawfully completed when Mauritius acceded to independence in 1968, following the detachment of the Chagos Archipelago (para. 174).

(1) There was no reason to reformulate or interpret restrictively the questions posed by the General Assembly. The references in the first question to certain resolutions of the General Assembly did not prejudge their legal content or scope. The first question did not submit to the Court a bilateral dispute over sovereignty between the United Kingdom and Mauritius. In...