52 A. AND OTHERS v. THE UNITED KINGDOM JUDGMENT “39. A State Party may take measures derogating from its obligations under the International Covenant on Civil and Political Rights pursuant to Article 4 (hereinafter called ‘derogation measures’) only when faced with a situation of exceptional and actual or imminent danger which threatens the life of the nation. A threat to the life of the nation is one that: (a) affects the whole of the population and either the whole or part of the territory of the State; and (b) threatens the physical integrity of the population, the political independence or the territorial integrity of the State or the existence or basic functioning of institutions indispensable to ensure and protect the rights recognised in the Covenant. 40. Internal conflict and unrest that do not constitute a grave and imminent threat to the life of the nation cannot justify derogations under Article 4.” Paragraph 54 of the Siracusa Principles continues as follows: “54. The principle of strict necessity shall be applied in an objective manner. Each measure shall be directed to an actual, clear, present, or imminent danger and may not be imposed merely because of an apprehension of potential danger.” 110. The United Nations Human Rights Committee, in General Comment No. 29 on Article 4 of the ICCPR (24 July 2001), observed in paragraph 2: “Measures derogating from the provisions of the Covenant must be of an exceptional and temporary nature.” VI. OTHER MATERIALS CONCERNING NON-DISCLOSURE OF EVIDENCE IN NATIONAL SECURITY CASES 111. In Charkaoui v. Minister of Citizenship and Immigration [2007] 1 SCR 350, McLachlin CJ, for the Supreme Court of Canada, observed in paragraph 53: “Last but not least, a fair hearing requires that the affected person be informed of the case against him or her, and be permitted to respond to it.” That right was not absolute and might be limited in the interests of national security (paragraphs 57-58); however, paragraph 64 provides: “... The judge is therefore not in a position to compensate for the lack of informed scrutiny, challenge and counter-evidence that a person familiar with the case could bring. Such scrutiny is the whole point of the principle that a person whose liberty is in jeopardy must know the case to meet. Here that principle has not merely been limited; it has been effectively gutted. How can one meet a case one does not know?” 112. In Hamdi v. Rumsfeld 542 US 507 (2004), O’Connor J, writing for the majority of the Supreme Court of the United States of America, said (p. 533):