Onuzi v Secretary of State for the Home Department [2025] EWCA Civ 1337: FTT’s role under s 40(3) confirmed as public-law review of causation; prolonged identity deception ordinarily material to naturalisation

Introduction

This Court of Appeal decision addresses when a naturalised British citizen may be deprived of citizenship because it was “obtained by means of” fraud, false representation, or concealment of a material fact under section 40(3) of the British Nationality Act 1981 (BNA 1981). The case sits at the intersection of three recurring issues: (1) the standard of review on appeals to the First-tier Tribunal (FTT) under section 40A BNA 1981 after the Court of Appeal’s decision in Chaudhry; (2) the meaning of “by means of” and materiality in the context of persistent identity deception extending into the naturalisation application; and (3) whether Home Office maladministration or concessionary grants of leave break the chain of causation for the purposes of section 40(3).

The appellant, Mr Betim Onuzi, entered the UK illegally in 1999, pursued an asylum claim using a false Kosovan identity, and consistently maintained this deception through his later applications for indefinite leave to remain (ILR) and for naturalisation. After the Home Office discovered the truth in 2020, the Secretary of State decided to deprive him of British citizenship under section 40(3).

The FTT allowed his appeal, finding the deception not causative because ILR (and thus citizenship) had followed from administrative errors and delay. The Upper Tribunal (UT) set aside that decision, applying the public-law review framework and remade the decision to dismiss the appeal. The central question for the Court of Appeal was whether the UT had applied the correct test and whether the Secretary of State’s causation and discretion decisions under section 40(3) were lawful.

Summary of the Judgment

The Court of Appeal dismissed the appeal. Reaffirming the framework clarified in Chaudhry v SSHD [2025] EWCA Civ 16 (and noting the Supreme Court’s reaffirmation of the public-law approach in U3 v SSHD [2025] UKSC 19), the Court held that:

• The FTT decides, as a matter of fact, whether there was fraud, false representation, or concealment (if disputed).
• The Secretary of State’s decisions on causation (whether citizenship was “obtained by means of” the wrongdoing) and on the exercise of deprivation discretion are reviewed by the FTT on public-law grounds (illegality, irrationality, procedural unfairness), not on a full merits re-hearing.
• Article 8 proportionality is for the FTT to decide, giving due weight to the Secretary of State’s policies and evaluations.

Applying that framework, the Court found no public-law error in the Secretary of State’s conclusion that, had the truth been known, the appellant would have been refused naturalisation on good character grounds. The chain of causation was not broken by the grant of ILR arising from maladministration because there had been no full disclosure of the deception at any point prior to naturalisation. The Court endorsed the UT’s approach and its reliance on the strong line of authority (including KV, Laci, and Daci) that it will be unusual for a person who obtained citizenship by deception to retain it.

Detailed Analysis

1. Precedents and Authorities Cited

• Chaudhry v SSHD [2025] EWCA Civ 16; [2025] KB 395: The Court adopts and applies the four-part approach at [54]:
  • (i) FTT finds the primary facts of fraud/false representation/concealment (if disputed).
  • (ii) The Secretary of State’s causation decision (that naturalisation was “obtained by means of” the wrongdoing) is reviewed on public-law grounds (Begum, para 71 principles).
  • (iii) The Secretary of State’s discretion to deprive is reviewed on public-law grounds.
  • (iv) The FTT itself determines any Human Rights Act issue (notably Article 8), giving due weight to the Secretary of State’s policies and evaluations, but ultimately deciding the proportionality question.

  Onuzi applies this framework to a fact pattern of long-running identity deception, confirming that the causation inquiry focuses on the naturalisation decision and the likely outcome had the truth been known.

• U3 v SSHD [2025] UKSC 19; [2025] 2 WLR 1041 and Begum (No. 1) [2021] AC 765:

  The Supreme Court in U3 reaffirmed the public-law standard of review for executive decisions in national security and deprivation contexts, previously crystallised in Begum. Although the Court in Onuzi stated it was unnecessary to draw on Begum given Chaudhry, both parties accepted Chaudhry as the controlling authority, itself aligned with Begum/U3.

• R (KV) v SSHD [2018] EWCA Civ 2483; [2018] 4 WLR 166:

  Leggatt LJ emphasised that, where deception was used and naturalisation would not have been granted without it, it is unusual for deprivation to be unfair, since deprivation restores the status quo ante ([19]). Onuzi reflects this logic, noting no suggestion that the appellant lost pre-existing rights by naturalising.

• Laci v SSHD [2021] EWCA Civ 769; [2021] 4 WLR 86:

  Underhill LJ endorsed the principle that only exceptionally will a person who obtained citizenship by deception be permitted to retain it. Onuzi reaffirms this high threshold and the centrality of good character.

• SSHD v Daci [2025] EWCA Civ 18:

  In a strikingly similar case involving a false identity at naturalisation, the Court held that continued deceit as an adult decisively undermined good character, and administrative delay in discovering the fraud did not render deprivation disproportionate ([39]-[40]). Onuzi follows this approach.

• Sleiman (deprivation of citizenship; conduct) [2017] UKUT 367 (IAC):

  Previously relied upon to argue that earlier deception may be irrelevant if ILR was granted under a concession. Following Chaudhry, its utility is limited; the chain-of-causation is broken only where there was full disclosure and an informed grant of leave or citizenship. The appellant ultimately accepted that Sleiman could not assist him.

• BA v SSHD [2018] UKUT 85 (IAC):

  Referenced in Laci for the proposition that retention of fraudulently obtained citizenship will only be exceptional. This sentiment underpins the trajectory of the modern caselaw and is reflected in Onuzi.

• Chimi [2023] UKUT 115 (IAC):

  UT guidance on structuring the analysis in deprivation appeals (condition precedent; discretion; Article 8), followed and applied at the UT’s resumed hearing in Onuzi.

2. The Court’s Legal Reasoning

(a) The correct appellate test under s 40A BNA 1981

The appeal was granted partly to clarify the “proper test” on appeal to the FTT in s 40(3) cases where the FTT had concluded that deception did not cause the grant of citizenship. The Court confirms that Chaudhry supplies the binding framework:

• The FTT does not perform a full merits re-determination of the Secretary of State’s causation or discretion decisions under section 40(3). Instead, it reviews those decisions for public-law error—illegality, irrationality (including failure to take into account relevant considerations), or procedural unfairness.
• Only the existence of fraud/false representation/concealment (if disputed) is determined as a primary fact-finding question by the FTT.
• Article 8 is determined by the FTT itself, albeit with due respect to the executive’s expertise and policies.

This approach displaces the appellant’s submission that the Upper Tribunal could only interfere with the FTT if the FTT’s findings were perverse. The FTT had applied the wrong legal test by substituting its view of causation and over-relying on a misreading of Chapter 55.7.4; the UT was right to set it aside.

(b) “By means of” under s 40(3): materiality and the chain of causation

The Court focuses on whether naturalisation in 2007 was “obtained by means of” fraud/false representation. On the facts, the appellant’s false identity and country-of-origin narrative were maintained consistently from asylum through to naturalisation, including a negative answer to the “good character” question and declarations asserting truthfulness despite the deception. The Secretary of State concluded in 2020 that, had the truth been known, the appellant would have been refused naturalisation on good character grounds; the Court found no public-law error in that conclusion and considered any other conclusion “unrealistic” on these facts.

Importantly, the Court addresses the alleged break in causation because ILR had been granted in 2006 against a backdrop of Home Office mistakes. The Court approves the UT’s position (reflecting the UT’s list at [45]) that the “chain of causation” is typically broken only where there has been full disclosure and a discretionary grant of leave or citizenship in full knowledge of the relevant facts. Here, there was never disclosure; thus, ILR arising from maladministration did not interrupt the causal link to naturalisation obtained by a dishonest concealment of a material fact.

(c) The role and limits of policy guidance (Chapter 55)

The FTT relied on Chapter 55.7.4 to suggest that previous deception “may be irrelevant” where ILR was granted under a concession. The UT (and, by necessary implication, the Court) considered this overbroad. Chapter 55.7.4 is an example-driven caveat—often engaged in family-wide concessions or country policies—where a person’s individual deception may genuinely be irrelevant to the status later relied upon for naturalisation if the grant was made independent of their deception and with the relevant facts known. The policy does not “blind the Home Office to relevant considerations going to good character” (UT at [18(a)]). Where the deception persists into the naturalisation application, it will normally be directly material to the good character assessment and so to the section 40(3) test.

(d) Article 8 proportionality

The FTT’s Article 8 reasoning was inadequate because it did not weigh the strong public interest in maintaining the integrity of nationality law, particularly given prolonged deception. In line with Daci, administrative delay in discovering the deception does not ordinarily render deprivation disproportionate, especially where the dishonesty continued into adulthood and into the naturalisation application itself. No special features—such as loss of pre-existing rights due to naturalisation (KV)—were present to tip the balance.

3. Impact and Implications

(a) For tribunals

• Standard of review settled: Following Chaudhry and now applied in Onuzi, the FTT must approach causation and discretion under section 40(3) by way of public-law review, not merits substitution. A failure to do so is an error of law.
• Fact-finding confined to fraud if disputed: Where fraud/false representation/concealment is accepted or proven, the tribunal’s task is not to re-run the Secretary of State’s counterfactual but to ask whether the Secretary of State’s causation conclusion was one reasonably open on the evidence and law.
• Limited role for “perversity” arguments: Attempts to confine the UT’s power to interfere with the FTT to perversity only are misconceived when the FTT has misdirected itself on the governing standard (public-law review).

(b) For practitioners acting for appellants

• Breaking the chain of causation is difficult absent full disclosure: Arguments that prior grants of leave (e.g., ILR) due to maladministration or delay sever causation will generally fail if the deception continued and there was no informed discretionary grant with the true facts known.
• Materiality through “good character” will often be decisive: Persistent identity deception—especially where expressly denied in the naturalisation form—almost invariably undermines the good character requirement. The Home Office’s counterfactual (“the application would have been refused for want of good character”) will be hard to dislodge on public-law grounds without compelling, case-specific evidence.
• Policy reliance has to be precise: Chapter 55.7.4’s concession example is narrow. Unless a genuine concession applied independent of the deception, and the decision-maker knew the truth, the guidance will not assist.
• Article 8 requires more than length of residence: Absent exceptional facts, family and private life built during a period of deception will rarely outweigh the public interest in deprivation (Laci, Daci). Evidence of exceptional hardship or loss of pre-existing rights is critical.

(c) For the Secretary of State and caseworkers

• Reasoned causation analysis: Decision letters should explain clearly why the deception was material to the naturalisation decision—most directly via the good character requirement, but also (if relevant) via residence or other statutory criteria. Onuzi endorses a clear, evidence-grounded statement that the application would have been refused had the truth been known.
• Use of guidance: When Chapter 55.7.4 is considered not to apply, decisions should briefly explain why any cited concession (family/country-wide policy) does not alter the assessment, and note the absence of full disclosure at the time of grant.
• Article 8 proportionality: Identify the public interest factors and address any compelling circumstances. Delay in discovery should be contextualised as neutral where the applicant continued the deception.

(d) Systemic effect and pending litigation

Onuzi consolidates the post-Chaudhry landscape by applying the public-law review framework to a straightforward case of persistent identity fraud. It confirms that ILR granted against a background of error does not usually break causation where deception persists to naturalisation. Together with Daci, this decision will guide the outcomes in similar cases and offers clarity pending and beyond related appeals (e.g., those identified at permission stage).

Complex Concepts Simplified

• Section 40(3) BNA 1981: The Secretary of State may deprive someone of citizenship obtained by fraud, false representation, or concealing a material fact. The key question is whether citizenship was “obtained by means of” the wrongdoing—i.e., whether the wrongdoing was causative.
• “By means of” and materiality: If the concealed truth would likely have led to refusal of naturalisation (often because the person was not of “good character”), the deception is material and causative.
• Good character: A statutory requirement for naturalisation. Prolonged dishonesty with the Home Office, including false identity claims and dishonest answers on the naturalisation form, typically means the requirement is not met.
• Chain of causation: The link between the wrongdoing and the grant of citizenship may be broken if, despite knowing the full truth, the Secretary of State granted leave or citizenship. Without full disclosure, administrative errors do not usually break the chain.
• Public-law review vs merits appeal: The FTT does not replace the Secretary of State’s judgment on causation/discretion with its own; it checks whether the Secretary of State’s decision was lawful, rational, and fair. Only the underlying facts of fraud (if disputed) are for the FTT to determine afresh.
• ELR/ILR: Exceptional Leave to Remain (now obsolete) and Indefinite Leave to Remain are immigration statuses. Naturalisation is a separate, later decision. Deception at earlier stages can be material to the later naturalisation decision, especially via the good character requirement.

Conclusion

Onuzi is a clear and robust application of the Chaudhry framework. It confirms that:

• On appeals under section 40A in section 40(3) cases, the FTT’s role is confined to fact-finding on fraud (if disputed) and public-law review of the Secretary of State’s causation and discretion decisions, with Article 8 decided by the FTT.
• Persistent identity deception that continues into the naturalisation application is ordinarily material to the good character assessment and thus satisfies the “obtained by means of” test under section 40(3).
• Administrative error or delay in granting earlier immigration status will not break the chain of causation absent full disclosure and an informed discretionary grant.
• Only unusually will a person who obtained citizenship by deception be permitted to retain it; delay in discovery rarely changes the analysis.

The case strengthens a consistent judicial message: nationality law depends on integrity at every stage. Where that integrity is compromised by protracted deception, deprivation is a legally orthodox and proportionate response.