Part 4 of the ATCSA applies only to foreign nationals. U.K. nationals cannot be detained under immigration powers. Indefinite detention without trial on the basis of criminal law powers would be incompatible with international human rights and domestic law, even where a public emergency existed and the U.K. sought formally to derogate from its human rights obligations.40 The power of detention under the act is therefore discriminatory on its face.
The United Kingdoms human rights obligations apply to U.K. nationals and non-nationals alike. The ICCPR obligates signatories to respect and to ensure to all individuals within its territory the rights recognized in the present Covenant (emphasis added), while the ECHR obliges signatories to secure [rights] to everyone within their jurisdiction.41 The U.N. Human Rights Committee has emphasized in relation to the ICCPR that the general rule is that each one of the rights of the Covenant must be guaranteed without discrimination between citizens and aliens.42 While international human rights law contemplates some distinctions between nationals and non-nationals, e.g. with respect to voting rights, in general discrimination in the guarantee of rights on the basis of nationality is forbidden.
The SIAC ruled that the derogation from the ECHR was unlawful because it did not comply with the non-discrimination provisions of the European Convention. The SIAC noted that the application of indefinite detention provisions would properly be confined to the alien section of the population only if, as the Attorney-General contends[,] the threat stems exclusively or almost exclusively from that alien section.43 As the SIAC then pointed out:
But evidence before us demonstrates beyond argument that the threat is not so confined. There are many British nationals already identified mostly in detention abroad who fall within the definition of suspected international terrorists, and it was clear from the submissions made to us that in the opinion of the [the UK government] there are others at liberty in the United Kingdom who could be similarly defined. In those circumstances we fail to see how the derogation can be regarded as other than discriminatory on the grounds of national origin.44
The Court of Appeal reversed the SIACs findings on discrimination, holding that the measures constituted a permissible distinction compatible with the U.K. governments obligations under human rights law. The court acknowledged the threat from terrorism posed by U.K nationals. Its reasoning rested on the fact that the right of an alien to reside in the U.K. was not unconditional, even if present circumstances prevented deportation.45
Given the obligation under the ECHR and ICCPR to respect the right of all persons present in the territory, the distinction between aliens who cannot be removed and nationals who have a right to remain provides an insufficient basis for different treatment. One is therefore left only with treatment based on nationality. The SIACs findings remain logically persuasive. The arrest of eight U.K. nationals by anti-terrorism police on March 30 in connection with an alleged bomb plot underscores the SIACs point that the threat is not confined to foreign nationals.46
The discriminatory nature of Part 4 was highlighted by the Joint Human Rights Committee in its February 2004 report: the Committee remains of the view that there is a significant risk that the powers under Part 4 violate the right to be free of discrimination under ECHR Article 14 because they have a particular impact on only part of the resident community of the United Kingdom.47 This conclusion implicitly rejects the distinction devised by the Court of Appeal.
The U.N. Commission on the Elimination of Racial Discrimination takes a similar position. In December 2003, it expressed deep concern about indefinite detentions under the act, and emphasized the obligation of states to ensure that measures taken in the struggle against terrorism do not discriminate in purpose or effect on grounds of race, colour, descent, or national or ethnic origin.48
 The protections offered to those charged with a crime are far more extensive, and it would be impossible to construct a derogation that would meet the requirements of necessity. Moreover, the protections accorded to criminal suspects are fundamental principles of English domestic law, which neither the courts nor parliament would permit the government to bypass.
 ICCPR Article 2; ECHR Article 1.
 U.N. Human Rights Committee, General Comment No. 15: The position of aliens under the Covenant, May 11, 1986. The Comment further emphasizes that non-citizens have the full right to liberty and security of the person.
 SIAC. A, X and Y and others,para. 94.
 SIAC, A, X and Y and others, para. 95.
 [A]n aliens right to reside in this country is not unconditional. True it is that the respondents cannot be deported, but that does not mean that they are in the same position as nationals. They are still liable to be deported, subject to the decision of SIAC on their personal circumstances, when and if this is practical. Court of Appeal, A, X and Y and others v. Secretary of State for the Home Department  EWCA Civ 1502, October 25, 2002, para. 50.
 Stephen Filder, Mark Huband, and Friederike Tiesenhausen Cave, Bomb-making material discovered in London warehouse following 24 dawn raids by five forces and MI5 officers, Financial Times, March 30, 2004; Rosie Cowan and Richard Norton-Taylor, MI5 agents foil bomb plot: Security services claim huge attack was halted with arrests after dawn raid by 700 police, The Guardian, March 30, 2004.
 Joint Committee on Human Rights, Sixth Report, 2003-04, summary, and para. 35.
 U.N. CERD, Concluding Observations: United Kingdom, December 10, 2003.