(1) As held in Deliallisi (British citizen: deprivation appeal: scope) [2013] UKUT 439 (IAC), in an appeal under section 40A of the British Nationality Act 1981 the Tribunal is required to determine the reasonably foreseeable consequences of deprivation.

(2) Whilst the Tribunal considering a section 40A appeal cannot pre-judge the outcome of any future legal challenge that the appellant might bring against a decision to remove, following deprivation, the Tribunal must nevertheless take a view as to whether, from its present vantage point, there is likely to be force in any future challenge: cf section 94 of the Nationality, Immigration and Asylum Act 2002 and paragraph 353 of the immigration rules. The stronger the potential case, the less likely it will be that the reasonably foreseeable consequences of deprivation will include removal.

(3) A person who had indefinite leave to remain in the United Kingdom, immediately before acquiring British citizenship, does not thereby become entitled to indefinite leave to remain, upon being deprived of such citizenship under section 40 of the 1981 Act. Leave to remain is effectively extinguished by becoming a British citizen, since the system of controls under the Immigration Act 1971 does not apply to British citizens.

(4) In a section 40A appeal, an appellant may rely on the ground that deprivation would have a disproportionate effect, as regards the rights flowing from citizenship of the EU, only if, on the facts, there is a “cross-border” element. The finding to the contrary in Deliallisi was reached per incuriam in the judgment of the Court of Appeal in G1 v Secretary of State for the Home Department [2012] EWCA Civ 867.

Source: AB (British citizenship: deprivation; Deliallisi considered) Nigeria [2016] UKUT 451 (IAC) (28 September 2016)