46 HASSAN v. THE UNITED KINGDOM – JUDGMENT when its armed forces were engaged in active hostilities in an armed conflict outside its own territory, had to afford the procedural safeguards of Article 5 to enemy combatants whom it took as prisoners of war, or suspected enemy combatants whom it detained pending determination of whether they were entitled to such status. In addition, insofar as the issue arose in the present case, the same principle had to apply in relation to the detention of civilians where this was “absolutely necessary” for security reasons, in accordance with Article 42 of the Fourth Geneva Convention (see paragraph 33 above). In the present case, since Tarek Hassan was captured and initially detained as a suspected combatant, Article 5 was displaced by international humanitarian law as lex specialis, or modified so as to incorporate or allow for the capture and detention of actual or suspected combatants in accordance with the Third and/or Fourth Geneva Conventions, such that there was no breach by the United Kingdom with respect to the capture and detention of Tarek Hassan. 89. In the alternative, if the Court were to find that Article 5 applied and was not displaced or modified in situations of armed conflict, the Government submitted that the list in Article 5 § 1 of permissible purposes of detention had to be interpreted in such a way that it took account of and was compatible with the applicable lex specialis, namely international humanitarian law. The taking of prisoners of war pursuant to the Third Geneva Convention, and the detention of civilians pursuant to the Fourth Geneva Convention, had to be a lawful category of detention under Article 5 § 1; it fell most readily as a “lawful detention” within Article 5 § 1(c). In this special context, the concept of “offence” within that provision could correctly be interpreted to include participation as an enemy combatant and/or challenging the security of the Detaining Power within Article 42 of the Fourth Geneva Convention. The key question for the purposes of Article 5 § 1 would then be whether the detention of Tarek Hassan was a “lawful detention” in the context of an international armed conflict; the Government submitted that it evidently was. Tarek Hassan was encountered by British forces as a “gunman”, armed with an AK-47 machine gun, on the roof of a house belonging to a general of the Al-Quds Army, where firearms as well as intelligence material were found. He was captured as a suspected combatant and British forces were lawfully entitled under international humanitarian law to capture and detain him until his status was finally determined. 90. The Government recognised that difficult issues might arise as to the applicability of Article 15 in relation to a case such as the present. Consistently with the practice of all other Contracting Parties which had been involved in such operations, the United Kingdom had not derogated; there had been no need to do so, since the Convention could and did accommodate detention in such cases, having regard to the lex specialis, international humanitarian law. The inclusion of Article 15 in the