Ashwathi Menon, Dr. D.Y Patil College of Law
Sakshi Belwal, Assam University Silchar
Editor: Jasmine Emmanuel, GLC Thrissur
BACKGROUND OF THE CASE
The Chagos island dispute has quite achieved the superstar status in the international legal community. This case is an international dispute between the United Kingdom and Mauritius on its claim over the sovereignty of the Chagos Archipelago which has paved the way to various political and diplomatic debates in the international legal community. The roots of this dispute can be traced back to 1965.
The Chagos Archipelago and Mauritius are each located in the Indian Ocean. They are separated, at the nearest point, by nearly 1,000 nautical miles of ocean. The Chagos Archipelago is located at approximately 1,150 nautical miles from the main island of Mauritius. The Chagos Archipelago was explored and named by the Portuguese in the sixteenth century. France then occupied the Archipelago in the eighteenth century, and administered it as a Dependency of the Île de France, as Mauritius was then known. The United Kingdom occupied the Island of Mauritius in 1810, during the Napoleonic Wars. By the Treaty of Paris of 30 May 1814, France ceded the Ile de France and all its dependencies (including the Chagos Archipelago) to the United Kingdom.
Between 1814 and 1965, the Chagos Archipelago was administered by the United Kingdom as a dependency of the colony of Mauritius. It was the 1953 election that marked the beginning of Mauritius’s move towards independence. In February 1964, discussions commenced between the United States of America and the United Kingdom regarding the use by the United States of certain British-owned islands in the Indian Ocean. The United States expressed an interest in establishing military facilities on the island of Diego Garcia.
In conjunction with the move toward Mauritian independence, the United Kingdom formulated a proposal to separate the Chagos Archipelago from the remainder of the colony of Mauritius and to retain the Archipelago under British control. According to Mauritius, the proposal to separate the Chagos Archipelago stemmed from a decision by the United Kingdom in the early 1960s to "accommodate the United States’ desire to use certain islands in the Indian Ocean for defence purposes." In 1965, the United Kingdom entered into the "Lancaster House Agreement" with Mauritian ministers to detach the Chagos Islands from Mauritius. And accordingly, in 1965, Chagos Island became a part of British Indian Ocean Territory. Later in 1966, the United Kingdom and the United States concluded a treaty regarding the use of Diego Garcia. Pursuant to the planned construction of a U.S. base on this island, the Chagossians were forcibly removed from the entire Archipelago.
On 1 April 2010, the United Kingdom announced the creation of a marine protected area in and around the Chagos Archipelago. On 20 December 2010, Mauritius instituted proceedings against the United Kingdom pursuant to Article 287 of the United Nations Convention on the Law of the Sea before an Arbitral Tribunal constituted under Annex VII of the Convention, challenging the creation of a marine protected area by the United Kingdom. In those proceedings, Mauritius submitted, inter alia, that (1) the United Kingdom was not entitled to declare a marine protected area or other maritime zones in and around the Chagos Archipelago as it was not a coastal State within the meaning of UNCLOS; (2) the United Kingdom was not entitled to declare unilaterally a marine protected area or other maritime zones because Mauritius had rights as a coastal State within the meaning of Articles 56, paragraph 1, and 76, paragraph 8, of UNCLOS;
On 18 March 2015, the Arbitral Tribunal constituted under Annex VII of UNCLOS rendered an award that it lacked jurisdiction in case of determining the claim of sovereignty over Chagos islands. Nonetheless, it stated that by establishing the marine protected area surrounding the Chagos Archipelago, the United Kingdom had breached its obligations under Article 2, paragraph 3, Article 56, paragraph 2, and Article 194, paragraph 4, of the Convention. 
ANALYSIS OF THE ADVISORY OPINION PASSED BY THE ICJ
In 2017, UNGA decided to take the advisory opinion of the ICJ in the said matter. The International Court of Justice (ICJ) delivered its Advisory Opinion on the two questions posed in the UN General Assembly's request.
1. First, had Mauritius' decolonisation been completed when it gained independence in 1968, after the excision of the Chagos Archipelago?
2. Secondly, what were the legal consequences flowing from the United Kingdom's continued administration of the Archipelago?
The Court found, unanimously, that it had the jurisdiction to give an advisory opinion under Article 65 of the statute.
Whether the process of decolonization of Mauritius was lawfully completed having regard to international law?
The court firstly set out to determine whether there existed the right to self-determination. The right to self-determination is a cardinal principle in the international law by which a country determines its own statehood and forms its own government The court stated that General Assembly resolution 1514(1960) (XV) declared that: all peoples have the right to self-determination, the colonial powers cannot place fetters on independence, and any disruption of the territorial integrity of a country is incompatible with the Charter. However, during the advisory proceedings, the United Kingdom and the United States contended that the right to self-determination emerged as a norm with the adoption of resolution 2625(XXV) in 1970 which states that the principle of equal rights and self-determination of peoples enshrined in the Charter of the United Nations embraces the right of all peoples freely to determine, without external interference, their political status and to pursue their economic, social and cultural development as well as the duty of every State to respect this right in accordance with the provisions of the Charter. They stated that this charter was passed in 1970 after Mauritius attained independence and so was irrelevant.
The ICJ ruled that the adoption of 1514 marked the crystallization of the right to self-determination. It stated that the 1965 Lancaster housing agreement does not express the consent and the Mauritian authorities hence were under no authority to agree to the detachment. In effect, the Court held that consent could only have been obtained through a referendum held before the decision was made. It, therefore, reached the conclusion that Mauritius' decolonization had not been lawfully completed in 1968.
The consequences under international law arising from the continued administration by the United Kingdom of the Chagos Archipelago
It decided that the United Kingdom's continuing administration of the Chagos Islands constitutes an internationally wrongful act for which it bears responsibility. In addition, the Court reaffirmed its view that self-determination manifests anerga omnes character (i.e. all states have a legal interest in safeguarding this right). It also stated that the United Kingdom thereby is under an obligation to respect the right of self-determination of Mauritius and enable it to resume control over Chargo Islands. The United Kingdom is a member of the United Nations is expected to respect the right of self-determination of another country.
Thus, one has analyzed critically the parameters on which the ICJ passed this unanimous advisory opinion. As it is an advisory opinion it is not binding on either of the parties to follow this. However, one can see that the advisory opinion has by far reflected very well on the issue at hand and passed out an acceptable judgement with regard to the international law. However, what has to be noted is that the ICJ has conveniently avoided addressing the certain issue of sovereignty. Secondly, ICJ also failed to address the relevance of the 1965 agreement, as it was agreed expressly by the Mauritian representatives and United Kingdom was not under any obligation to carry out with a referendum so how can one invalidate such an agreement. Thirdly, ICJ has left out to mention third party rights of United States involved here.
The dispute has not really reached a conclusive stage as there are a lot of matters at hand which has not yet been addressed properly. The opinion of ICJ is not obligatory to be followed and it finally relies upon the General Assembly as to how to adopt this opinion.
 Legal Consequences of the Separation of the Chagos Archipelago from Mauritius in 1965, Advisory Opinion https://www.icj-cij.org/files/case-related/169/169-20190225-01-00-EN.pdf 18th August 20  Legal Consequences of the Separation of the Chagos Archipelago from Mauritius in 1965, Advisory Opinion https://www.icj-cij.org/files/case-related/169/169-20180215-WRI-01-00-EN.pdf 18th August 20  Stephen Allen “The Chagos Advisory Opinion and the decolonization of Mauritius” Vol 23:Issue 2 https://www.asil.org/insights/volume/23/issue/2/chagos-advisory-opinion-and-decolonization-mauritius 18th August 20  Legal Consequences of the Separation of the Chagos Archipelago from Mauritius in 1965, Advisory Opinion https://www.icj-cij.org/files/case-related/169/169-20190225-01-00-EN.pdf 18th August 20 Stephen Allen “The Chagos Advisory Opinion and the decolonization of Mauritius” Vol 23:Issue 2 https://www.asil.org/insights/volume/23/issue/2/chagos-advisory-opinion-and-decolonization-mauritius 18th August 20