circumstances amount to torture or cruel, inhuman or degrading treatment or punishment.133 If there are substantial grounds134 for believing that a person whose nationality has been withdrawn would suffer human rights violations as a consequence of such withdrawal, this consideration must also be part of the assessment of whether withdrawal of nationality would be proportionate to the aim pursued. Consideration as to whether expulsion, return or extradition would be disproportionate should include taking into account “the existence in the State concerned of a consistent pattern of gross, flagrant or mass violations of human rights.”135 States must also consider whether a person may be subject to arbitrary detention upon removal to another country. Where an individual is detained (including for enforcement of immigration laws and in the context of military detention) as a result of withdrawal of nationality, such detention must not be arbitrary. Arbitrary detention includes situations in which there is no oversight or review as to the length of detention, which may in some circumstances amount to torture or cruel, inhuman or degrading treatment or punishment.136 This is particularly relevant where an individual no longer has the right to reside in a State as a result of withdrawal of nationality but has no other nationality or place of (legal) residence, and as a result, is detained for an indefinite period.137 A State should ensure that in all cases where it withdraws nationality from an individual and withdraws its permission for that person to reside in its territory, another State has formally agreed to admit that person and provide them with protection consistent with international human rights law.138 Absence of such formal agreement 133 This is particularly relevant where an individual no longer has the right to reside in a State as a result of withdrawal of nationality but has no other nationality or place of (legal) residence, and as a result, is detained for an indefinite period. See Anudo Ochieng Anudo v Republic of Tanzania, African Court on Human and Peoples’ Rights, Application No. 012/2015, 22 March 2018, https://www.refworld.org/cases,AfCHPR,5d7bb4784.html, paras. 118, 120-121: The African Court on Human and People’s Rights opined that a breach of an individual’s right to liberty and security of person and protecting against arbitrary arrest and detention under Article 9(1) of the International Covenant on Economic and Social Rights was a consequence of his being arbitrarily deprived of nationality. The individual in question had been detained following arbitrary deprivation of nationality and inability to legally reside in the country to which he was expelled. See also Human Rights Council, Report of the Special Rapporteur on torture and other cruel, inhuman or degrading treatment or punishment, 26 February 2018, A/HRC/37/50, para. 27: “The Human Rights Committee has repeatedly considered that "the combination of the arbitrary character of the [...] detention, its protracted and/or indefinite duration, the refusal to provide information and procedural rights to the [detainees] and the difficult conditions of detention are cumulatively inflicting serious psychological harm upon them, and constitute treatment contrary to article 7 of the Covenant." 134 See e.g., Agiza v Sweden, Communication no. 233/2003, UN Committee against Torture, 20 May 2005, CAT/C/34/D/233/2003, paras. 13.2-13.5. 135 Convention against Torture and Other Cruel, Inhuman or Degrading Treatment or Punishment 1465 UNTS 85, Article 3(2). International Convention for the Protection of All Persons from Enforced Disappearance 2716 UNTS 3, Article 16(2). 136 See e.g., Human Rights Council, Report of the Special Rapporteur on torture and other cruel, inhuman or degrading treatment or punishment, 26 February 2018, A/HRC/37/50, paras. 26-29. 137 See e.g., Human Rights Council, Report of the Working Group on Arbitrary Detention, 24 December 2012, A/HRC/22/44. 138 UNHCR, UNHCR intervention before the Supreme Court of Canada in the case of Manickavasagam Suresh (Appellant) and the Minister of Citizenship and Immigration, the Attorney General of Canada (Respondents), 8 March 2001, https://www.refworld.org/docid/3e71bbe24.html, paras. 52 and 78. UNHCR > GUIDELINES ON STATELESSNESS NO.5 36