Seventeen persons have been certified as suspected international terrorists under the ATCSA.10 Certification by the Home Secretary requires only a reasonable belief that a foreign national present in the U.K. is a threat to U.K. national security and a suspicion11 that the person is a terrorist as defined by the act.12 Of the seventeen persons certified to date, twelve are being indefinitely detained without charge under the act, one is being detained under other unspecified powers, one has been released on bail (and is effectively under house arrest) and two have left the U.K. One has been released following a successful appeal against certification. Eight of those detained under the ATCSA have been in custody for more than two years. The men are being held in category A maximum security prisons and in one case a high security psychiatric hospital.
The ATCSA detainees are foreign nationals whom the U.K. government says it would deport to their home countries were it not for the risk that they would be tortured if sent there. Unlike the due process guarantees suspended by the U.K., the prohibition against torture cannot be derogated from under any circumstances.13 Because of the threat that the U.K. government says the men pose, it is unwilling to allow them to remain at liberty in the U.K. The government also argues that because its evidence against the men is based on classified intelligence, it cannot successfully prosecute those certified under ATCSA. The men are therefore trapped in limbo. The U.K. governments argument that the men are free to leave at any time is fallacious. If the men were able to leave safely, they would surely have followed the two men certified under the act who have already done so, rather than face continued indefinite detention. Equally, if it were safe for the men to leave voluntarily, the U.K. could also safely deport them.14
International law does not permit indefinite detention without trial under any circumstances. Immigration detention is only lawful under the European Convention on Human Rights (ECHR) where action is being taken with a view to deportation or extradition.15 It is settled law that the detaining state must be taking action with due diligence to deport (or extradite) the detained person.16 Where the person cannot be removed, the state clearly cannot meet the due diligence test, and the detention is incompatible with human rights law. In order to make ATCSA compatible with the U.K.s obligations under international and regional human rights law and with the U.K. Human Rights Act (which incorporates the ECHR into domestic law), the U.K. government therefore had to derogate from human rights obligations.
Derogation required the U.K. government to make a formal declaration that there was a state of emergency threatening the life of the nation and making the suspension of rights necessary. On December 18, 2001, the U.K. government formally derogated from article 5(1)(f) of the ECHR, which protects against deprivation of liberty except for purposes of deportation or extradition.17 On the same date, the government informed the U.N. Secretary-General that a public emergency within the meaning of Article 4(1) of the International Covenant on Civil and Political Rights (ICCPR) exists in the United Kingdom and of its intention to avail itself of the right of derogation from article 9 of that treaty, governing the deprivation of liberty.18
Those detained under the ATCSA are able to challenge their detention in the Special Immigration Appeals Commission (SIAC), but with far fewer procedural guarantees than are accorded to those charged with a crime. Established in 1997 in the wake of the landmark Chahal case in the European Court of Human Rights,19 SIAC is a special tribunal that reviews deportation cases involving national security issues. SIAC uses a system of dual hearings and legal representation adapted from the Canadian courts, with each detainee assigned a special advocate, in addition to his own legal representative of choice. The special advocates, all of them experienced barristers, have security clearance enabling them to review the classified material that forms much of the evidence on which terrorist certifications are based. They attend special closed sessions of the SIAC, from which the detainee and his legal representative of choice are excluded. The special advocate is not permitted to discuss the case with the detainee or his designated legal representative once the special advocate has been granted access to the classified material, unless the special advocate first obtains permission from SIAC. The system also includes open hearings, where non-classified evidence is heard, and which the detainee and his designated legal representative are permitted to attend.
 Home Office, Anti-Terrorism, Crime & Security Act 2001 Detainees under Part 4, n.d. [online], http://www.homeoffice.gov.uk/docs3/atcsa_detainees.html (retrieved April 16, 2004).
 The exact standard of proof required for a reasonable belief and suspicion is not clear but clearly is lower than either the criminal standard of proof in the UK, which is beyond a reasonable doubt, or the civil standard of proof, a balance of probabilities.
 According to s.21 of the act, terrorist means a person who (a) is or has been concerned in the commission, preparation or instigation of acts of international terrorism, (b) is a member of or belongs to an international terrorist group, or (c) has links with an international terrorist group. ATCSA, s.21.
 Article 3 of the European Convention for the Protection of Human Rights and Fundamental Freedoms (ECHR). The absolute nature of article 3 ECHR includes protection from being returned to a place where one will be subject to torture, and cruel, inhuman and degrading treatment or punishment (non-refoulement) Soering v. United Kingdom (1989) 11 EHRR 439, para. 91. Article 3.1 of the U.N. Convention against Torture to which the United Kingdom is a state party, contains an explicit protection against refoulement, No State Party shall expel, return (refouler) or extradite a person to another State where there are substantial grounds for believing he would be in danger of being subjected to torture.
 The logic of this argument has been criticized by Council of Europe Committee for the Prevention of Torture. CPT, Report to the Government of the United Kingdom on the visit to the United Kingdom carried out by CPT from 17 to 21 February 2002, February 12, 2003. Moreover, at least one of the detainees, Mahmoud Abu Rideh, is a stateless Palestinian. (Audrey Gillan, Terror suspect tells of torture that led to death wish, The Guardian, May 5, 2004).
 ECHR Article 5(1)(f).
 Chahal v. United Kingdom, (1997) 23 EHRR 413, para. 113.
 The derogation was initiated by way of an order made by the UK Government a month earlier. An order is a form of delegated legislation that does not require parliamentary approval. The order also had the effect of suspending the UKs obligation under domestic law to respect ECHR article 5(1)(f). The Human Rights Act 1998 (Designated Derogation) Order 2001, S.I. 2001, No. 3644. (Entry into force on November 13, 2001).
 International Helsinki Federation, Anti-Terrorism Measures, Security and Human Rights: Developments in Europe, Central Asia and North America in the Aftermath of September 11, April 2003, pp. 34, 85.
 Chahal v. United Kingdom. The case, heard by the European Court of Human Rights, concerned an Indian national wanted in India on terrorism charges, whom the U.K. held in detention pending deportation for six years, while the issue of whether he would be exposed to torture if extradited to India was litigated. The Chahal case is often used to illustrate the absolute prohibition against torture under article 3 ECHR, and was explicitly referred to by the U.K. in the order derogating from article 5(1)(f) ECHR.