1. To our regret we are not able to agree with the reasoning and the findings of the Tribunal on Mauritius’ Submissions Nos. 1 and 2; we, however, concur with the findings on Submissions Nos. 3 and 4, although not with all the relevant reasoning.

2. This Opinion will concentrate on the areas of disagreement, namely the characterization of the legal dispute between the Parties and the jurisdiction of the Tribunal concerning Submissions Nos. 1 and 2 of Mauritius. It will also deal with some issues concerning the merits of the case.

A. CHARACTERIZATION OF THE DISPUTE

1. Final Submission No. 1 of Mauritius1

3. The Parties differ on the characterization of the dispute. Mauritius states that its case is that the MPA is unlawful under the Convention. The United Kingdom, for its part, argues that the dispute is one about sovereignty over the Chagos Archipelago. In its Final Submission No. 1, Mauritius requested the Tribunal to adjudge and declare that the United Kingdom is not entitled to declare an “MPA” or other maritime zones because it is not the “coastal State within the meaning of inter alia Articles 2, 55, 56 and 76 of the Convention.” During the oral hearing, Mauritius put it this way: “[t]he central question before this Tribunal is not whether the United Kingdom has sovereignty, it is whether the United Kingdom for the purposes of the Convention is ‘the coastal State’ and was, as such, entitled to act as it does”.2 This statement was made without prejudice to the fact that there exists a longstanding dispute between the parties about sovereignty over the Chagos Archipelago.