HASSAN v. THE UNITED KINGDOM – JUDGMENT 51 was under an obligation to the United Nations Security Council to place the applicant in internment and that, because of Article 103 of the United Nations Charter, this obligation had to take primacy over the United Kingdom’s obligations under the Convention. It was the Government’s case that an obligation to intern the applicant arose from the text of United Nations Security Council Resolution 1546 and annexed letters and also because the Resolution had the effect of maintaining the obligations placed on occupying powers under international humanitarian law, in particular Article 43 of the Hague Regulations (see Al-Jedda, cited above, § 107). The Court found that no such obligation arose. It was only before the Commission, in Cyprus v. Turkey, nos. 6780/74 and 6950/75, Report of the Commission of 10 July 1976, volume 1, that a question arose similar to that in the present case, namely whether it was compatible with the obligations under Article 5 of the Convention to detain a person under the Third and Fourth Geneva Conventions in the absence of a valid derogation under Article 15 of the Convention. In its report, the Commission refused to examine possible violations of Article 5 with regard to detainees accorded prisoner of war status, and took account of the fact that both Cyprus and Turkey were parties to the Third Geneva Convention (see § 313 of the Report). The Court has not, until now, had the opportunity to review the approach of the Commission and to determine such a question itself. 100. The starting point for the Court’s examination must be its constant practice of interpreting the Convention in the light of the rules set out in the Vienna Convention on the Law of Treaties of 23 May 1969 (see Golder v. the United Kingdom, judgment of 21 February 1975, Series A no. 18, § 29, and many subsequent cases). Article 31 of the Vienna Convention, which contains the “general rule of interpretation” (see paragraph 34 above), provides in paragraph 3 that there shall be taken into account, together with the context, (a) any subsequent agreement between the parties regarding the interpretation of the treaty or the application of its provisions; (b) any subsequent practice in the application of the treaty which establishes the agreement of the parties regarding its interpretation; and (c) any relevant rules of international law applicable in the relations between the parties. 101. There has been no subsequent agreement between the High Contracting Parties as to the interpretation of Article 5 in situations of international armed conflict. However, in respect of the criterion set out in Article 31 § 3(b) of the Vienna Convention (see paragraph 34 above), the Court has previously stated that a consistent practice on the part of the High Contracting Parties, subsequent to their ratification of the Convention, could be taken as establishing their agreement not only as regards interpretation but even to modify the text of the Convention (see, mutatis mutandis, Soering v. the United Kingdom, 7 July 1989, §§ 102-103, Series A no. 161 and Al-Saadoon and Mufdhi v. the United Kingdom, no. 61498/08, § 120, ECHR 2010). The practice of the High Contracting Parties is not to derogate