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World Court Digest

I. Substantive International Law - First Part
7.9. Specific Treaties
7.9.13. 1891 Boundary Convention Between Netherlands and Great Britain

¤ Case Concerning Sovereignty over
Pulau Ligitan and Pulau Sipadan
(Indonesia v. Malaysia)
Judgment of 17 December 2002

[p. ] 36. ... Indonesia relies essentially on Article IV of the 1891 Convention in support of its claim to the islands of Ligitan and Sipadan. That provision reads as follows:

“From 4° 10' north latitude on the east coast the boundary-line shall be continued eastward along that parallel, across the Island of Sebittik: that portion of the island situated to the north of that parallel shall belong unreservedly to the British North Borneo Company, and the portion south of that parallel to the Netherlands.”

The Parties disagree over the interpretation to be given to that provision.


41. The Court notes that the Parties differ as to how the preposition “across” (in the English) or “over” (in the Dutch) in the first sentence of Article IV of the 1891 Convention should be interpreted. It acknowledges that the word is not devoid of ambiguity and is capable of bearing either of the meanings given to it by the Parties. A line established by treaty may indeed pass “across” an island and terminate on the shores of such island or continue beyond it.

The Parties also disagree on the interpretation of the part of the same sentence which reads “the boundary-line shall be continued eastward along that parallel [4° 10' north]”. In the Court’s view, the phrase “shall be continued” is also not devoid of ambiguity. Article I of the Convention defines the starting point of the boundary between the two States, whilst Articles II and III describe how that boundary continues from one part to the next. Therefore, when Article IV provides that “the boundary-line shall be continued” again from the east coast of Borneo along the 4° 10' N parallel and across the island of Sebatik, this does not, contrary to Indonesia’s contention, necessarily mean that the line continues as an allocation line beyond Sebatik.

The Court moreover considers that the difference in punctuation in the two versions of Article IV of the 1891 Convention does not as such help elucidate the meaning of the text with respect to a possible extension of the line out to sea, to the east of Sebatik Island (see also paragraph 56 below).

42. The Court observes that any ambiguity could have been avoided had the Convention expressly stipulated that the 4° 10' N parallel constituted, beyond the east coast of Sebatik, the line separating the islands under British sovereignty from those under Dutch sovereignty. In these circumstances, the silence in the text cannot be ignored. It supports the position of Malaysia.

43. It should moreover be observed that a “boundary”, in the ordinary meaning of the term, does not have the function that Indonesia attributes to the allocation line that was supposedly established by Article IV out to sea beyond the island of Sebatik, that is to say allocating to the parties sovereignty over the islands in the area. The Court considers that, in the absence of an express provision to this effect in the text of a treaty, it is difficult to envisage that the States parties could seek to attribute an additional function to a boundary line.

[pp. ] 46. The Court considers that the Explanatory Memorandum appended to the draft Law submitted to the Netherlands States-General with a view to ratification of the 1891 Convention, the only document relating to the Convention to have been published during the period when the latter was concluded, provides useful information on a certain number of points.

First, the Memorandum refers to the fact that, in the course of the prior negotiations, the British delegation had proposed that the boundary line should run eastwards from the east coast of North Borneo, passing between the islands of Sebatik and East Nanukan. It further indicates that the Sultan of Bulungan, to whom, according to the Netherlands, the mainland areas of Borneo then in issue between Great Britain and the Netherlands belonged, had been consulted by the latter before the Convention was concluded. Following this consultation, the Sultan had asked for his people to be given the right to gather jungle produce free of tax within the area of the island to be attributed to the State of North Borneo; such right was accorded for a 15-year period by Article VII of the Convention. As regards Sebatik, the Memorandum explains that the island’s partition had been agreed following a proposal by the Dutch Government and was considered necessary in order to provide access to the coastal regions allocated to each party. The Memorandum contains no reference to the disposition of other islands lying further to the east, and in particular there is no mention of Ligitan or Sipadan.

47. As regards the map appended to the Explanatory Memorandum, the Court notes that this shows four differently coloured lines. The blue line represents the boundary initially claimed by the Netherlands, the yellow line the boundary initially claimed by the BNBC, the green line the boundary proposed by the British Government and the red line the boundary eventually agreed. The blue and yellow lines stop at the coast; the green line continues for a short distance out to sea, whilst the red line continues out to sea along parallel 4° 10' N to the south of Mabul Island. In the Explanatory Memorandum there is no comment whatever on this extension of the red line out to sea; nor was it discussed in the Dutch Parliament.

The Court notes that the map shows only a number of islands situated to the north of parallel 4° 10'; apart from a few reefs, no island is shown to the south of that line. The Court accordingly concludes that the Members of the Dutch Parliament were almost certainly unaware that two tiny islands lay to the south of the parallel and that the red line might be taken for an allocation line. In –this regard, the Court notes that there is nothing in the case file to suggest that Ligitan and Sipadan, or other islands such as Mabul, were territories disputed between Great Britain and the Netherlands at the time when the Convention was concluded. The Court cannot therefore accept that the red line was extended in order to settle any dispute in the waters beyond Sebatik, with the consequence that Ligitan and Sipadan were attributed to the Netherlands.

48. Nor can the Court accept Indonesia’s argument regarding the legal value of the map appended to the Explanatory Memorandum of the Dutch Government. The Court observes that the Explanatory Memorandum and map were never transmitted by the Dutch Government to the British Government, but were simply forwarded to the latter by its diplomatic agent in The Hague, Sir Horace Rumbold. This agent specified that the map had been published in the Official Journal of The Netherlands and formed part of a Report presented to the Second Chamber of the States-General. He added that “the map seems to be the only interesting feature of a document which does not otherwise call for special comment”. However, Sir Horace Rumbold did not draw the attention of his authorities to the red line drawn on the map among other lines. The British Government did not react to this internal transmission. In these circumstances, such a lack of reaction to this line on the map appended to the Memorandum cannot be deemed to constitute acquiescence in this line.

It follows from the foregoing that the map cannot be considered either an “agreement relating to [a] treaty which was made between all the parties in connection with the conclusion of the treaty”, within the meaning of Article 31, paragraph 2 (a), of the Vienna Convention, or an “instrument which was made by [a] part[y] in connection with the conclusion of the treaty and accepted by the other parties as an instrument related to that treaty”, within the meaning of Article 31, paragraph 2 (b), of the Vienna Convention.

[pp. ] 51. The Court considers that the object and purpose of the 1891 Convention was the delimitation of boundaries between the parties’ possessions within the island of Borneo itself, as shown by the preamble to the Convention, which provides that the parties were “desirous of defining the boundaries between the Netherland possessions in the Island of Borneo and the States in that island which are under British protection” (emphasis added by the Court). This interpretation is, in the Court’s view, supported by the very scheme of the 1891 Convention. Article I expressly provides that “[t]he boundary ... shall start from 4° 10' north latitude on the east coast of Borneo” (emphasis added by the Court). Articles II and III then continue the description of the boundary line westward, with its endpoint on the west coast being fixed by Article III. Since difficulties had been encountered concerning the status of the island of Sebatik, which was located directly opposite the starting point of the boundary line and controlled access to the rivers, the parties incorporated an additional provision to settle this issue. The Court does not find anything in the Convention to suggest that the parties intended to delimit the boundary between their possessions to the east of the islands of Borneo and Sebatik or to attribute sovereignty over any other islands. As far as the islands of Ligitan and Sipadan are concerned, the Court also observes that the terms of the preamble to the 1891 Convention are difficult to apply to these islands as they were little known at the time, as both Indonesia and Malaysia have acknowledged, and were not the subject of any dispute between Great Britain and the Netherlands.

52. The Court accordingly concludes that the text of Article IV of the 1891 Convention, when read in context and in the light of the Convention’s object and purpose, cannot be interpreted as establishing an allocation line determining sovereignty over the islands out to sea, to the east of the island of Sebatik.