decision and the assessment of the consequences on the applicant’s private life. 40. This Court examines diligence in both procedural and substantive terms. This includes assessing whether authorities have taken appropriate steps to verify relevant facts and the foreseeable consequences of the deprivation.77 The Court has found that where domestic courts fail to examine evidence capable of being determinative of nationality status without explanation, the decision is not accompanied by the necessary procedural safeguards and must be regarded as arbitrary.78 41. Procedural safeguards must be practical and effective (not merely formal), and include effective judicial oversight, timely notification of the individual, and an accessible right of appeal. Individuals must be afforded a genuine opportunity to participate in proceedings and to present evidence relevant to assess statelessness and the impact on their private life.79 Where significant restrictions affect a person’s ability to gather evidence and communicate with their lawyer, or they are otherwise unable to participate meaningfully in proceedings (e.g. due to being outside the territory), particular weight must be given to whether the process ensured a fair balance and equality of arms. 42. The intervenors submit that authorities and courts must diligently assess whether deprivation of nationality will foreseeably result in statelessness. Where that inquiry is not undertaken, deprivation will be arbitrary and in breach of Article 8. 43. Due diligence should follow international legal standards and guidance on the determination of statelessness, in line with States’ duty to prevent statelessness. These affect the quality and adequacy of procedures for assessing nationality. Determining statelessness in deprivation of nationality cases 44. Under Article 53 ECHR, Contracting States must not interpret the ECHR so as to fall below their international obligations to prevent statelessness, including under the Convention on the Reduction of Statelessness (1961 Convention), which has been widely ratified and to which the United Kingdom is a party.80 The duty to avoid conduct leading to statelessness forms part of customary international law 81 and sets limits on States’ ability to deprive individuals of their nationality. UNHCR has published authoritative guidance on the interpretation and application of the 1961 Convention (see Annex I). 45. Despite this, there is consistent evidence that Contracting States fail to implement these obligations in practice when depriving individuals of their nationality by failing to duly assess whether an individual will be rendered stateless. 46. In the UK, successive legislative changes have expanded deprivation powers. These are used more frequently than in most other States, including in national-security contexts, and have a disproportionate impact on British Muslims.82 UK law includes a narrowly framed power permitting deprivation that results in statelessness, but it has never been exercised.83 There have, however, been several cases where a deprivation 77 Johansen v. Denmark, op. cit., §§ 58-60; A.A. v. Denmark, op. cit., §§ 5-6; See also UK Home Office, Deprivation of British citizenship: Caseworker Guidance, Version 5.0, 14 January 2026, p. 7. 78 Ahmadov v. Azerbaijan, op. cit., §§ 52-54. 79 See Usmanov v. Russia, op. cit., § 63, citing Ramadan v. Malta, op. cit., §§ 86-89. 80 See Article 8(1) of the Convention on the Reduction of Statelessness, 30 August 1961, 989 UNTS 175; AIRE Centre and ENS, Written Submissions in Pham v the United Kingdom, 19 April 2021, §§ 14-15. 81 Council of Europe, Explanatory Report to the European Convention on Nationality, § 33. 82 Between 2010-2024, the UK made 223 deprivation orders on the ground that it was conducive to the public good. See reports by the House of Commons and the Joint Committee on Human Rights (Annex I). 83 Section 40(4A) of the BNA 1981. The Home Office claims that there are no known examples of a 9

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