On 18 March 2015, an arbitral tribunal constituted under Annex VII of the United Nations Convention on the Law of the Sea (‘UNCLOS’) rendered a decision on the dispute between the United Kingdom and Mauritius relating to the Chagos Marine Protected Area. The dispute arose in 2010 after the United Kingdom unilaterally decided to create a marine protected area (‘MPA’) in the British Indian Ocean Territory (‘BIOT’), which is comprised of the Chagos Archipelago. Mauritius instituted proceedings the same year, alleging that the creation of the MPA was in violation of the UNCLOS (articles 2, 55, 56, 63, 194 and 300) and other rules of international law applicable between the parties, in particular the Lancaster House Undertakings of 1965. Through those undertakings, the Chagos Archipelago was detached from Mauritius before its independence, a number of conditions were set for the future return of the islands to Mauritius, and certain rights were conferred to the latter (see para. 77 of the Award for a reference to the specific undertakings).
In its prayer for relief, Mauritius asked the Tribunal to declare that:
- The United Kingdom is not entitled to declare a MPA because it is not the coastal State under UNCLOS.
- Mauritius has rights as the coastal State, and the United Kingdom cannot, therefore, unilaterally declare a MPA.
- The United Kingdom shall take no steps that may prevent the Commission on the Limits of the Continental Shelf from making future recommendations to Mauritius regarding the Chagos Archipelago.
- The MPA is incompatible with the substantive and procedural obligations of the United Kingdom under UNCLOS and the UN Fish Stocks Agreement.
These arbitral proceedings can be seen as an attempt by Mauritius to shed light on its longstanding differences with the United Kingdom over the Chagos Archipelago. Mauritius generally does not recognize the BIOT, claims sovereignty over the islands comprising the archipelago, and believes that its excision in 1965 was contrary to international law, in particular the UN Charter. Both States disagree on several further issues regarding the resettlement of Chagossians, which occurred between 1968 and 1973 (for further reference, see this related judgment of the European Court of Human Rights in 2012). As argued below, the Tribunal took a narrow approach to the dispute that does little to solve its underlying problems.
Lack of jurisdiction regarding Mauritius’ first three submissions
The Tribunal decided not to deal with three of Mauritius’ claims because it lacked jurisdiction under articles 288 and 286 of the UNCLOS. The main challenge of the United Kingdom to the first two claims was that they were not related to a dispute under UNCLOS, but were rather an attempt to seek a settlement of the sovereignty dispute between the two States over the Chagos Archipelago. The policy basis for the United Kingdom’s argument is that allowing for an overly broad interpretation of article 288 of UNCLOS would open the door for abuses of the jurisdictional clause, since any State with a sovereignty dispute over territory could bring a claim under the argument that another State is not the “coastal State”.
In the Award, the Tribunal upholds this position. It begins by explaining that UNCLOS provides no guidance on identifying the coastal State in cases where sovereignty over territory is disputed, and one would have to apply other rules of international law to identify such a State. According to the Tribunal, two main questions require an answer in this regard: (1) what is the nature of the dispute and (2) to what extent article 288 allows a tribunal to determine issues of land sovereignty as a necessary precondition to the determination of rights and duties of coastal States.
Regarding the first question, after looking at the background of the dispute and Mauritius’ pleadings during the proceedings, which were “replete with assertions of Mauritian sovereignty over the Chagos Archipelago”, the Tribunal decided that the nature of the dispute was one of sovereignty over territory (see paras. 209-212 of the Award). In the Tribunal’s perspective, sovereignty was the core issue and the question of identifying the coastal State was merely a manifestation of the latter.
Regarding the second question, the Tribunal analysed two main issues. First, whether the drafters of the Convention contemplated jurisdiction over issues of land sovereignty. Second, whether article 298(1)(a)(i), by providing the possibility of excluding maritime boundaries disputes from compulsory jurisdiction, implies that land sovereignty disputes fall within the general jurisdiction of a court or tribunal established under UNCLOS. The Tribunal found no relevant evidence in the preparatory work of UNCLOS and decided that it would be unreasonable to expect that States allow for the exclusion of maritime boundaries disputes, while at the same time establishing compulsory jurisdiction over land sovereignty disputes, which are “more fundamental” and sensitive, without reservations. Jurisdiction under article 288 would therefore not extend to land sovereignty disputes (paras. 213-217).
As one can see, the Tribunal adopted a narrow approach to its jurisdiction under the UNCLOS. The reasoning is persuasive and the exercise of judicial constraint is understandable given the sensitivity of the case at hand, but the judgment does deserve some comments.
In this case, the perspective from which one approaches the dispute plays a very important role. The Tribunal decided to see the case from a certain angle, which, as Judges Wolfrum and Kateka pointed out in their dissenting opinion, is in no way the only possible perspective. Land sovereignty was seen as the main component of the case, whilst the maritime issues were put in a secondary position. An opposite appreciation of the case was also possible, but Mauritius’ legal strategy unnecessarily shifted the attention to the issue of sovereignty. It is interesting to note the Tribunal’s view that “in some instances a minor issue of territorial sovereignty could indeed be ancillary to a dispute concerning the interpretation or application of the Convention”. How is one to differentiate between major and minor sovereignty disputes? This determination would not only need to be made on a case-by-case basis, but would also be very subjective, since it would depend on the judge or arbitrator’s connection and sensitivities towards a dispute. How a State presents a case will also have an impact on these determinations.
While the Tribunal declined its jurisdiction to deal with the first three submissions, it upheld jurisdiction regarding the fourth one. Here, no analysis identifying the coastal State took place, although the discussion focused on article 297 of the UNCLOS, which refers to disputes concerning the interpretation and application of the Convention with regard to the exercise of sovereign rights and jurisdiction by…the coastal State! The Tribunal’s initial refusal to identify the coastal State transformed, therefore, into a tacit recognition of the United Kingdom as such. While this does not solve the sovereignty dispute between the two States, this approach seems to be in contradiction with the Tribunal’s previous reasoning on the lack of UNCLOS guidance identifying the coastal State. Apparently, that identification is possible, but the Tribunal was not clear on this aspect. It assumed that the coastal State is the former colonial power, which nowadays de facto controls the territory.
The merits
This article will conclude with some brief remarks on the interesting points of law raised by the discussion of the merits and their possible precedential value.
- Estoppel (paras. 434-448): The Tribunal relied on the principle of estoppel to reaffirm the international legal nature of the Lancaster House Undertakings of 1965. According to the Tribunal, the undertakings became an international agreement after Mauritius became independent and any possible problem with Mauritius’ consent at the time they were made is solved by the posterior conduct of both States (representations and reliance). Regarding the element of detrimental reliance, the Tribunal found that this occurred in the form of foregone opportunities: if the Lancaster House Undertakings and their posterior reaffirmation by the United Kingdom had not taken place, Mauritius would have had the chance to assert its sovereignty more aggressively. As for the legitimacy of the reliance, the Tribunal considered that it is not necessary for a representation to take the form of a binding unilateral act, which would otherwise blur the distinction between two different sources. More informal and ambiguous representations are sufficient for the purposes of estoppel, provided the repetition and reliance are present.
- The scope of application of articles 2(3) and 56(2) of the UNCLOS (paras. 499-536): Both articles are concerned with the role of other norms of international law when applying UNCLOS and until now, their scope has been somewhat unclear. Article 2(3) establishes that sovereignty in the territorial sea must be exercised “subject to other rules of international law”, while article 56(2) specifies that the exercise of rights and performance of duties in the exclusive economic zone (EEZ) should be made “having due regard” of rights and duties of third States. The question before the Tribunal was to what extent the Lancaster House Undertakings are applicable within these articles.
Regarding article 2(3), the Tribunal noted that the reference to international law extends only to general rules of international law, and not to bilateral agreements between States. The applicable rules of international law, however, oblige the United Kingdom to “observe its undertakings in good faith”. Regarding article 56(2), the Tribunal finds that there is no specific obligation of conduct. What each State must do to have “due regard” of others’ rights and obligations in the EEZ depends on the specific circumstances of the case (although usually it will involve some kind of consultation). The Tribunal finally found the obligations under both articles to be equivalent and declared that the United Kingdom violated UNCLOS because it failed to consult with Mauritius before the creation of the MPA and to balance its own rights with Mauritius’ rights arising from the undertakings.