A/HRC/18/54 the right to liberty and security of person, and that no one should be subjected to arbitrary arrest or detention. Therefore, while international law allows that administrative immigration detention may legitimately be applied in certain individual cases, it is widely held that such a deprivation of liberty should be exceptional, and used only as a measure of last resort. 42. In addition, international law provides that the detention of children, including children in the context of migration, should generally be avoided. The Special Rapporteur on the human rights of migrants has affirmed that it is never in the best interests of children to be detained, and that children should not be detained on the basis of their migratory status or irregular entry to the country.36 43. The prohibition of arbitrary detention means that any decision to detain must be guided by principles of reasonableness, necessity, proportionality and non-discrimination. These principles also require States to consider other ways to achieve their objectives without interfering with the right to liberty and security of person. So-called “alternatives to detention” can take the form of reporting requirements, bails or bonds, open centres and directed residence, or electronic monitoring. The Working Group on Arbitrary Detention advised that “alternative and noncustodial measures, such as reporting requirements, should always be considered before resorting to detention.”37 In the regional context, article 15 (1) of the European Union Returns Directive asserts that immigration detention should be preceded by a consideration of “other sufficient but less coercive measures [that] can be applied effectively in a specific case.” 44. The impulse to use detention as a deterrent measure could also be questioned in the light of recent research, which indicates that there is no empirical evidence to support the conclusion that detention deters irregular migration or discourages persons from seeking asylum. 38 2. Collective expulsion 45. The absolute prohibition of collective expulsion is well established in international and regional human rights law.39 Article 22 (1) of the International Convention on the Rights of All Migrant Workers and Members of Their Families provides that “migrant workers and members of their families shall not be subject to measures of collective expulsion. Each case of expulsion shall be examined and decided individually.” Article 4 of Protocol 4 to the European Convention on Human Rights similarly provides that “collective expulsion of aliens is prohibited.” 46. In accordance with this principle, all non-nationals enjoy protection from collective expulsion, including those with an irregular status. Accordingly, each person in a group of non-nationals intercepted by a State has the right not to be returned or removed without 36 37 38 39 12 See A/HRC/11/7. See also A/HRC/15/29. See E/CN.4/1999/63/Add.3, para. 33. See also E/CN.4/1999/63, para. 69, guarantee 13. UNHCR, “Back to Basics: The Right to Liberty and Security of Person and ‘Alternatives to Detention’ of Refugees, Asylum-Seekers, Stateless Persons and Other Migrants”, April 2011. See also International Detention Coalition, “There are alternatives: A handbook for preventing unnecessary immigration detention”, 2011. In its general comment No. 15, the Human Rights Committee confirmed that “laws or decisions providing for collective or mass expulsions” would entail a violation of article 13 of the International Covenant on Civil and Political Rights. The Inter-American Commission on Human Rights further elaborated that “an expulsion becomes collective when the decision to expel is not based on individual cases but on group considerations, even if the group in question is not large.” Report on Terrorism and Human Rights, OAS Doc. OEA/Ser.L/V/II.116, Doc. 5, rev. 1 corr., 22 October 2002.