21. With respect to detention on grounds of public order or security, the Human Rights Committee has stated that such detention must not be arbitrary and must comply with the provisions of the ICCPR. If the person is a ‘clear and serious threat to society which cannot be contained in any other manner’, then such preventive detention may be justified.431 The guarantees under the Covenant would still apply. 22. The Special Rapporteur on the human rights of migrants has addressed the relationship between counter-terrorism measures and migration. She has pointed out that: ‘[T]he strengthening of security policies and the tendency to consider migration as a matter falling under State security plans pose a threat to the human rights of migrants’. She has recommended that there should be ‘regard for the individual history of the persons in question’ and ‘procedural safeguards and guarantees established by international human rights law and national law in criminal proceedings be applied to any form of detention’. 23. Detention on the grounds of mental health may be permissible. For example, a detention of an individual after their threatening and aggressive behaviour following the opinion of three psychiatrists, and the regular review of this detention, was not a violation of Article 9 of the ICCPR.432 24. The European Court has established a five-stage test for the detention of persons on the ground of mental health: a. The mental disorder must be established by objective medical expertise b. The nature and degree of the disorder must be sufficiently extreme to justify the detention c. Detention should only last as long as the medical disorder and its required severity persists d. In cases where detention is potentially indefinite, periodical reviews must take place by a tribunal which has powers to discharge e. Detention must take place in a hospital, clinic or other appropriate institution authorised to detain such persons.433 Detention for the purposes of deportation and extradition: 25. Individuals requesting asylum can be detained but such decisions should be periodically reviewed.434 26. Detention should only continue for as long as it can be justified, for example, to conduct an investigation, or to prevent an individual from absconding. Detention beyond the required period will then be unlawful even if the individual entered into the state illegally.435 Detention in the context of an international armed conflict 27. In Hassan v UK, the European Court held that detention would also be permitted in the context of an international armed conflict provided it was 431 Communication 66/1980, D. A. Cámpora Schweizer v. Uruguay, 12 October 1982, para. 18.1. Communication 754/1997, A. v. New Zealand, 3 August 1999. 433 Winterwerp v Netherlands, European Court, 24 October 1979. 434 Communication 560/1993, A. v. Australia 3 April 1997. 435 Ibid. 432 86