would undermine the State’s duty to protect; impede investigation and accountability; or expose the individual concerned to further harm. 35. Heightened Duties in Respect of Children: Heightened and immediate obligations under Article 4 are owed in respect of children. Article 4(c) of the Council of Europe Convention on Action against Trafficking in Human Beings recognises that, “the recruitment, transportation, transfer, harbouring or receipt of a child for the purpose of exploitation shall be considered ‘trafficking in human beings’ even if this does not involve any of the means set forth in subparagraph (a) of this article.”25 Moreover, as the UN Special Rapporteur on trafficking in persons, especially women and children has noted, “children must always be treated primarily as victims and the best interest of the child must always be a primary consideration.”26 This requires a low identification threshold, a duty of urgency, and a requirement to prioritise protection over punitive measures. The failure to act on a credible suspicion of child trafficking and, instead, adopt a measure increasing the risk of harm, constitutes a violation of the Article 4 obligations. Article 4 directly relevant to States’ obligation to consider arbitrariness prior to citizenship deprivation 36. Where credible indicators of trafficking arise, prior to a citizenship deprivation decision, the State is required to assess whether the individual concerned was a trafficking victim, and whether any protective duties arose from that status. Failure to carry out such an assessment would be materially significant, as a finding that the individual concerned was a trafficking victim would directly affect considerations of whether or not citizenship deprivation may violate international law, including the Convention. 37. The prohibition of arbitrary deprivation of nationality is well established under international law. 27 Citizenship deprivation on national security grounds is presumptively arbitrary. This presumption may only be displaced if deprivation is, at a minimum, carried out in pursuance of a legitimate purpose; provided for by law; necessary; proportionate; and in accordance with procedural safeguards.28 Even if all conditions are satisfied, a deprivation of nationality may still be arbitrary and unlawful if it leads to a violation of other Convention rights, in particular non-derogable rights. 38. Legitimate purpose: Deprivation must be carried out in pursuance of a legitimate purpose “that is consistent with international law and, in particular, the objectives of international human rights law,”29 and is clearly defined.30 Deprivation aimed at facilitating expulsion or preventing return directly limits the concerned State’s ability to facilitate protection and recovery as per Article 4. Such a purpose also contravenes the 25 Article 4(a) reads as follows: “‘Trafficking in human beings’ shall mean the recruitment, transportation, transfer, harbouring or receipt of persons, by means of the threat or use of force or other forms of coercion, of abduction, of fraud, of deception, of the abuse of power or of a position of vulnerability or of the giving or receiving of payments or benefits to achieve the consent of a person having control over another person, for the purpose of exploitation. Exploitation shall include, at a minimum, the exploitation of the prostitution of others or other forms of sexual exploitation, forced labour or services, slavery or practices similar to slavery, servitude or the removal of organs”, Council of Europe Convention on Action against Trafficking in Human Beings, Article 4(a). 26 Submission by the UN Special Rapporteur on trafficking in persons, especially women and children, in H.F. and M.F. v. France (App. No. 24384/19) and J.D. and A.D. v. France (App. No. 44234/20) before the European Court of Human Rights, para. 24. 27 See, Eritrea-Ethiopia Claims Commission, Partial Award (Civilian Claims) (2004) 26 UNRIAA 195, para. 57; Proposed Amendments to the Naturalisation Provision of the Constitution of Costa Rica (Advisory Opinion OC-4/84) IACtHR Series A No. 4 (19 January 1984) paras 33-34; Expelled Dominicans and Haitians v Dominican Republic (2014) IACtHR Series C No. 282, para. 253; Anudo Ochieng Naudo v. United Republic of Tanzania (2018) AfCHPR App no 012/2015, para. 76; Tamás Molnár, ‘The Prohibition of Arbitrary Deprivation of Nationality under International Law and EU Law: New Perspectives’ (2015) Hungarian Yearbook of International Law and European Law 67, 74; Maureen Manly and Laura van Waas, ‘The Value of the Human Security Framework in Addressing Statelessness’, in Alice Edwards and Carla Ferstman, (eds), Human Security and Non-Citizens (CUP 2010), 63; Alice Edwards, ‘The Meaning of Nationality’ in Alice Ewards and and Laura van Waas (eds), Nationality and Statelessness under International Law (CUP 2014) 25-26. 28 UN Human Rights Council, ‘Human rights and arbitrary deprivation of nationality: Report of the Secretary General’ (2013) UN Doc A/HRC/25/28, para 4; Anudo Ochieng Anudo v Tanzania (2018), Application no. 012/2015, para 79; ECtHR, K2 v. United Kingdom (2017), Application no. 42387/13, para 50. Similar reasoning can be found in consecutive cases, such as Johansen v. Denmark (2022), Application no. 27801/19. 29 UN Human Rights Council, ‘Human rights and arbitrary deprivation of nationality: Report of the Secretary General’, A/HRC/13/34 (2009), para. 25. 30 Glion Recommendation (2019), p. 9. 6