INTERNATIONAL COURT OF JUSTICE
COUR INTERNATIONALE DE JUSTICE
LEGAL CONSEQUENCES OF THE SEPARATION OF THE CHAGOS ARCHIPELAGO
FROM MAURITIUS IN 1965 (REQUEST FOR ADVISORY OPINION)
EFFETS JUR/DIQUES DE LA SEPARATION DEL 'ARCH/PEL DES CHA GOS DE
MAURICE EN 1965 (REQUETE POUR AVISCONSULTATIF)
Judge Cancado Trindade: As recalled in paragraph (a) of the V.N. General Assembly's
request for an Advisory Opinion of the International Court of Justice (General Assembly
resolution 71/292 of 22.06.2017), the General Assembly refers to obligations enshrined into
successive pertinent resolutions of its own, as from 1960, namely: General Assembly
resolutions 1514(XV) of 14.12.1960, 2066(XX) of 16.12.1965, 2232(XXI) of 20. 12. I 966, and
2357(XXIJ) of 19.12.1967.
In the course of the present oral advisory proceedings, references were often made to such
resolutions by several delegations o.f participants.
In your understanding, what are the legal consequences ensuing from the formation of
customary international law, with the significant presence of opinio juris communis, for
ensuring compliance with the obligations stated in those General Assembly resolutions?
Response of the United Kingdom of Great Britain and Northern Ireland
1. The UK's central contention remains that the Court should exercise its discretion so as
not to give an Advisory Opinion in answer to the request put to it by the General
Assembly further to its Resolution 71/292, adopted on 22 June 2017. The UK's response
to the present question is without prejudice to that position.
2. The question is understood to concern the relevance, if any, of four General Assembly
resolutions in the present advisory proceedings. The United Kingdom has dealt with this
matter at length in its written and oral statements 1•
3. In particular, the United Kingdom stated:
a. General Assembly resolutions are, subject to very few exceptions, not binding
under international law and only recommendatory in nature2. The Court itself has
1 StGB, paras. 8.27-8.54, 9.6-9.7; CoGB, paras. 2.95, 3.21, 4.20-4.26, 4.35-4.43, 4.50; CR 20 18/21; CR
2018/21, p. 27, para. 5 (Wordsworth); pp. 45-46, paras. 14-16; pp. 47-50, paras. 22-27; p. 52, para. 33 (Webb).
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urged "all due caution" in examining the content and conditions of a resolution to
ascertain whether there is a gradual evolution of' opinio j1.,ris3.
b. Resolution l 5 l 4(XV) ( 1960): The negotiating records and explanations of vote
reveal that there were divided views to its meaning that were not resolved by the
time of its adoption4
• The United Kingdom itself expressed concerns several times
during the negotiations5
• Nine States abstained, including colonial powers
(Belgium, France, Portugal, Spain, United Kingdom, and United States). Even
States that voted in favour expressed misgivings or emphasised that the resolution
was aspirational6
• When it came to negotiating the Friendly Relations Declaration
in 1970, resolution 1514 was considered and then deliberately omitted7.
Resolution 1514 marked an important "stage" in the development of international
law on self-determination 8, but it did not reflect States' acceptance of a customary
obligation at that time.
c. Resolution 2066(XX) (1965): This resolution uses non-binding language,
including when referring back to resolution l 5 l 4(XV) ("request[ ed]" that the
provisions of the resolution be observed in relation to Mauritius). It contains no
condemnation of the United Kingdom nor any statement that it acted in breach of
binding international law9
• It was adopted with 18 abstentions, including the
United Kingdom.
d. Resolutions 2232(XXI) (1966) and 2357(XXII) (1967): These were omnibus
resolutions on 25 Territories expressing "deep concern", but not creating any
binding legal obligations for Member States10
•
2 StGB, paras. 8.32 and 8.67; CoGB, para. 4.20.
3 StGB, para. 8.32; Military and Paramilitary Activities in and against Nicaragua (Nicaragua v. United States
of America), Merits, Judgment, lCJ Reports 1986, p. 14 at para. 188; Report of the International Law
Commission on its 701
h Session, UN Doc. An3/ IO (31 August 2018), p. 148, para. ( 6) of the commentary to
draft conclusion 12.
4 StGB, paras. 8.40 -8.44; CoGB, paras. 4.20-4.23; CR 2018/21, p. 48, para. 24 (Webb).
s StGB, para. 8.45.
6 UN Doc. A/PV.947 (Dec. 14, 1960), para. 60 (The Netherlands) (UN Dossier No. 74); UN Doc.
A/PV .946 (Dec. 14, 1960), para. 12 (Sweden) (UN Dossier No. 73 ); UN Doc. A/PY .945 (Dec. 13, 1960), para.
188 (Austria) (UN Dossier No. 72); ; CR 2018/21, p. 48, para. 24 (Webb).
7 StGB, paras. 8.47-8.48.
'Western Sahara, Advisory Opinion, IC.J. Reports 1975. p. 12, at para. 56 (quoting Legal Consequences of the
Continued Presence of South Africa in Namibia (South West Africa) notwithstanding Security Council
Resolution 276 (/970), Advisory Opinion, f C.J. Reports 1971, p.16, at para. 52).
9 StGB, paras. 8.49-8.54; CoGB, para. 4.50;
10 StGB, para. 8. 7.
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4. Even if one or more of the four resolutions provided some evidence of an emerging
opinio juris, that evidence is not of "the significant presence of opinio juris communis". It
is, moreover, not supported by the extensive and virtually uniform State practice required
for the formation of customary international law11
• As the International Law
Commission's Draft Conclusions on the Identification of Customary International Law
provide, "A provision in a resolution adopted by an international organization ... may
reflect a rule of customary international law if it is established that the provision
corresponds to a general practice that is accepted as law (opinio juris)". 12 Notably, the
General Assembly passed no further resolutions regarding Mauritius and the Chagos
Archipelago from 1967 to 2017.
5. The question also asks about the legal consequences for ensuring compliance with the
(implied) "obligations stated in those General Assembly resolutions". The United
Kingdom observes that the wording of this question ("stated'') goes further than the
Request in implying that resolutions generate binding obligations under customary
international law. Questions (a) and (b) of the Request refer to "obligations reflected in
General Assembly resolutions" ( emphasis added).
6. In the United Kingdom's view, the General Assembly's Request in resolution 71/292
(2017) does not provide a legal basis for concluding that the four General Assembly
resolutions cited in Question (a) "reflected" customary international law at the time they
were adopted (1960-1967). As the Court stated in the Kosovo Advisory Opinion,
where a matter is capable of affecting the answer to the question posed, "[i]t would
be incompatible with the proper exercise of the judicial function for the Court to
treat that matter as having been determined by the General Assembly.''13
7. The United Kingdom has explained in its written pleadings that this wording seems
chiefly to be aimed at pointing the Court to what those who drafted the question
11 CR2018/21, p. 48, para. 23 (Webb).
12 Report of the International Law Commission on its 701
" Session, UN Doc. A/73/10 (31 August 2018), p. 121,
draft conclusion 12(3) (emphasis added). Paragraph (8) of the commentary (p 149) points out that "A provision
of a resolution cannot be evidence of a rule of customary international law if practice is absent, different or
inconsistent."
13 Accordance with International law of the Unilateral Declaration of Independence in Respect of Kosovo,
Advisory Opinion, I.C.J. Reports 2010, p. 403, at para. 52.
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(Mauritius) see as part of the applicable law1
'
1
• ln doing so, it incorrectly and
inappropriately assumes that the content of obligations, if any, "renected" in the
named General Assembly resolutions are legally binding on Stales, including the
United Kingdom 15
• This is not the case because of their status as Assembly
resolutions, their text, their context, and the circumstances of their adoption 16
•
8. As the Court observed in the Namibia Advisory Opinion, resolution 1514 (XV) was a
"further important stage" in the development of international law on self-detem1ination17
;
it was not the culmination of that evolution. To the extent that the language in these
resolutions may reflect important steps in the development of customary international law
on self-determination, the resolutions do not demonstrate that it was binding customary
international law in the period 1960-1967.
9. If this approach is somehow wrong (it is not) and there were obligations under customary
international law reflected in the resolutions in 1960-1967, no legal consequences would
ensue in relation to the detachment of the Chagos Archipelago because Mauritius
consented to the detachment and reaffirmed its consent on multiple occasions postindependence
18
•
10. If all the above were somehow wrong (it is not), then the legal consequences would have
to be based on the 1965 Agreement as interpreted by the Arbitral Tribunal in its binding
Award of 18 March 2015, and in this respect the United Kingdom respectfully refers to
paragraph 9.20 of its Written Statement of 15 February 2018.
14 StGB, paras. 8.7, 9.7.
15 StGB, para. 9.7; see also cites to pleadings in footnote 1 above.
16 Ibid.
17 Legal Consequences for States of the Continued Presence of South Africa in Namibia (South West Africa)
Notwithstanding Security Council Resolution 276 (1970), Advisory Opinion, l C.J. Reports I 971, p. 31, para.
52.
18 StGB, paras 3.38-3.50; CoGB, paras. 2.86-2.96; CR 2018/21, p. 9, para. 18; p. 15, para. 41; pp 21-41, paras.
66-77 (Buckland); pp. 29-30, para. 8; p. 34, para. 15, p. 37, para. 22; p. 39, para. 27; p. 40, para. 30
(Wordsworth); p. 44, para. 8 (Webb); p. 54, para. 6; pp. 57-58, paras. 14-18 (Wood)
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Written Reply of the United Kingdom to the question put by Judge Cançado Trindade at the end of the hearing held on 5 September 2018