principle of non-expulsion of nationals under which the State has obligations both to the individual and their freedom of movement,31 and to fellow-States.32 39. Provided for by law: Deprivations of nationality must conform with both international and domestic law, both to its letter and its object, to avoid an outcome that is unjust, illegitimate or unpredictable. 33 This includes the rules regarding deprivations rendering a person stateless, where the 1961 Convention is applicable, or where statelessness is independently relevant to the arbitrariness assessment. Legislative provisions, such as Section 40 of the British Nationality Act 1981, featuring grounds for citizenship deprivation on the basis of it being “conducive to the public good,” are imprecise and overly broad, and thereby violate the principle of legality. Moreover, Section 40 does not clarify the Secretary of State’s duties and obligations when a deprivation decision will likely engage other obligations, which, in turn, are also relevant “to the public good.” These include the State’s obligations of investigation, protection and recovery in relation to trafficking victims. By contrast, the 1961 Convention on the Reduction of Statelessness only permits citizenship deprivation that may result in statelessness on exceptional grounds, based on conduct “seriously prejudicial to the vital interests of the State.”.34 40. Necessary: Deprivation must be necessary for achieving the legitimate purpose.35 With regard to Article 8, “necessity” entails that “the interference must correspond to a pressing social need, and, in particular, must remain proportionate to the legitimate aim pursued.”36 If there is a less intrusive, less permanent, more proportionate way of achieving the same purpose, which does not interfere with other Convention rights, the State is obliged to pursue this other means. Given that citizenship deprivation and prohibition from re-entry directly impact the State’s ability to fulfil its obligations to trafficking victims, the question of necessity then also relates to Article 4. In assessing whether an interference was “necessary,” it is the State’s duty to also demonstrate the existence of the pressing security, social, or economic (and so forth) need behind the interference.37 The fact that a State maintains a two-tiered citizenship structure, under which those born citizens with no (theoretical) access to another citizenship can never be deprived of their citizenship,38 is demonstrative of the fact that the State has at its disposal other less intrusive means of achieving the same policy objectives (for those whose citizenship cannot be stripped).39 41. Proportionate: States must undertake an individualised proportionality assessment in determining whether to deprive nationality. The assessment must include whether: i) the immediate and long-term impact of citizenship deprivation on the rights of the individual, their family, and on society is proportionate to the legitimate purpose being pursued; ii) deprivation is the least intrusive means of achieving the stated legitimate 31 Human Rights Committee, ‘General Comment No. 27: Freedom of movement (article 12)’ (1999) CCPR/C/21/Rev.1/Add.9, para. 21. ECtHR, Naumov v. Albania (2005), Application no. 10513/03, para. 5. See also the case of e CH/02/8679, 192-3 (Human Rights Chamber of Bosnia and Herzegovina): The Chamber declared denationalisation a violation of the ECHR, Protocol 4, Article 3, if undertaken for the “sole purpose” of expulsion. The Chamber reached this conclusion based on reading the absolute prohibition on the expulsion of nationals in conjunction with Art. 17 ECHR. Otherwise, the Chamber argued, “if States could simply withdraw the citizenship of one of their citizens in order to expel him without being in violation of Article 3 of Protocol No. 4 to the Convention, then the protection of the right enshrined in that provision would be rendered illusory and meaningless”. 32 This is widely recognised in early international law scholarship and in discussions at the 1930 League of Nations Hague Conference, as set out in Guy Goodwin-Gill, ‘Deprivation of Citizenship, Statelessness, and International Law’ (5 May 2014). He cites, among others, Lauterpacht’s work from 1933 which sets out that “The indiscriminate exercise by a State of the right of denationalising its subjects, when coupled with the refusal to receive them when deported from a foreign country, constitutes an abuse of rights which could hardly be countenanced by an international tribunal”. H. Lauterpacht, The Function of Law in the International Community (Oxford University Press 1933; repr’d 2011), 309 as cited in G. Goodwin-Gill, ‘Deprivation of Citizenship, Statelessness, and International Law’ (5 May 2014) p. 7. 33 Article 8(4) 1961 Convention: A Contracting State shall not exercise a power of deprivation permitted by paragraphs 2 or 3 of this Article except in accordance with law, which shall provide for the person concerned the right to a fair hearing by a court or other independent body. 34 Article 8(3)(a)(ii) of the 1961 Convention on the Reduction of Statelessness; Glion Recommendation (2019), p. 9.; UNHCR, ’Tunis Conclusions‘ (2014), para. 68. 35 ICCPR, Art. 12(3); Art. 52(1) Charter of Fundamental Rights of the EU; HRC General Comment No. 31, para. 6: “State Parties must refrain from violation of the rights recognised by the Covenant, and restrictions on any of those rights must be permissible under the relevant provisions of the Covenant. Where such restrictions are made, States must demonstrate their necessity and only take such measures as are proportionate to the pursuance of legitimate aims in order to ensure continuous and effective protection of Covenant rights.” 36 ECtHR, Piechowicz v. Poland (2012), Application no. 20071/07, para. 212. 37 ECtHR, Piechowicz v. Poland (2012), Application no. 20071/07, para. 212. 38 Reprieve and Runnymede, Stripped: The Citizenship Divide, December 2025. 39 Mutatis mutandis, A. and Others v. the United Kingdom [GC] - 3455/05, Judgment 19 February 2009. 7