Self-Determination in Light of the International Court of Justice’s Opinion in the Chagos Case

Abstract

In its Advisory Opinion in Legal Consequences of the Separation of the Chagos Archipelago from Mauritius in 1965, delivered in 2019, the International Court of Justice (ICJ) was of the view that the decolonisation of Mauritius by the United Kingdom had not been lawfully completed when it achieved independence in 1968. This was due to the separation of the Chagos Archipelago in 1965. After dismissing various challenges to the exercise of its advisory jurisdiction, including the argument that the issue at stake was a territorial dispute between the States and that its jurisdiction was, therefore, being misused to circumvent the UnitedKingdom’s lack of consent to contentious proceedings, the ICJ felt it necessary to explore the nature, scope and content of the right to self-determination and whether it had been validly exercised in this instance. The ICJ found that self-determination had become established as a legal right in the context of decolonisation by the time Mauritius was in the process of securing its independence in the 1960s and that a corollary of the right was that of the territorial integrity of a non-self governing territory, which had not been respected in the case of Mauritius. Accordingly, the United Kingdom’s continued administration of the Chagos Archipelago constituted an ongoing internationally wrongful act, entailing international responsibility, which the United Kingdom was under an obligation to put an end to as soon as possible. While it was for the United Nations (UN) General Assembly to determine how the decolonisation of Mauritius was to be realised, in view of the fact that the right to self- determination has an erga omnes character, the ICJ called on all States to co-operate with the UN to that end.