Court of Appeal creates new law for the approach to assessing the risk of a breach of Article 3 ECHR (17 June 2026)

The Court of Appeal has introduced the concept of a “chain of causation” when Article 3 of the European Convention on Human Rights (ECHR) is relied upon to resist deportation.

In Secretary of State for the Home Department v OSB [2026] EWCA Civ 647, the court allowed the Home Office's appeal and held that the deportation of a Nigerian national suffering from paranoid schizophrenia would not breach Article 3. The First-Tier Tribunal had allowed OSB’s appeal on the basis that there was “a real risk” that deportation would lead to inhuman and degrading treatment, which is the classic test.

The Secretary of State appealed to the Upper Tribunal on the basis that the reasoning in the decision was flawed. That was rejected by the Upper Tribunal who also pointed out that the appeal was inconsistent with the way that the Secretary of State had argued the appeal in the First-Tier. Undeterred, the Secretary of State appealed again, now raising a further new argument that it was not reasonable to hold her responsible for subsequent events in Nigeria, should OSB commit further crimes there.

Background

The appellant, a Nigerian national referred to as OSB, entered the UK in 2000 using a false passport. Following the refusal of his immigration application and the exhaustion of his appeal rights in 2008, he remained in the UK and subsequently committed a number of serious criminal offences. All of those offences were committed in periods in which he had ceased taking his medication. He was sentenced to an indefinite hospital order. The Secretary of State later sought his deportation.

Previous tribunal findings had concluded that OSB had family support available in Nigeria, access to psychiatric treatment and medication, and that there was no greater risk of treatment non-compliance in Nigeria than in the UK. As a result, earlier tribunals found that deportation would not breach either Article 3 or Article 8 ECHR.

The First-tier Tribunal Decision

The matter returned to the First-tier Tribunal following further litigation and a deterioration in OSB's mental health.

Although Judge Loke accepted that medication would be available in Nigeria and that the risk of relapse was no greater there than in the UK, she found that there was a real risk that if deported OSB would stop taking his medication, relapse, and commit further offences, rejecting the Secretary of State’s arguments to the contrary. This was not surprising given that given that at the time OSB had very recently been refused release from a secure hospital by a Mental Health Review Tribunal on precisely the basis that there was exactly that risk.

The tribunal concluded there was a real risk that, following such a chain of events, OSB would be detained in “harsh and life-threatening “conditions where adequate medical treatment would not be available. On that basis, the appeal was allowed under Article 3.

The Court of Appeal's Findings

The Court of Appeal, having praised the preparation and presentation of this important case by both parties, overturned that decision.

The central issue was whether the tribunal's reasoning relied on an impermissibly speculative chain of events. The court concluded that it did. Giving judgment, the Court of Appeal found there were "too many links in the chain of causation" between deportation and the feared Article 3 breach. A “chain of causation” is a familiar legal concept which is utilised in claims in Tort, but has not previously been applied to Art. 3 risk assessments.

The court emphasised that the possibility that an individual might in future stop medication, relapse, commit criminal offences, be detained and then receive inadequate treatment was too remote to establish an Article 3 violation.

Importantly, the court sought to distinguish deportation cases from extradition cases. In extradition proceedings, detention is often an immediate and inevitable consequence of removal. By contrast, in this case, imprisonment depended upon a series of hypothetical future events.

Significance for Practitioners

The facts of the case illustrate how far - reaching this new approach is. There was no suggestion that Judge Loke’s assessment that there was a “real risk” of a rapid and irreversible decline in his health such as to breach Article 3 was irrational, or not supported by the evidence, yet the introduction of the novel (for this type of case) concept of a “chain of causation” was sufficient to reverse that decision.

Duncan Lewis are seeking permission to appeal to the Supreme Court.

Conclusion

The Court of Appeal's decision is likely to be cited frequently in future cases involving assessment of Art. 3 risks. It is hoped that the Supreme Court will clarify the correct basis of assessment.

About Jenna McKinney and James Packer

This matter was handled by Immigration Director Jenna McKinney

Public Law Director James Packer, a solicitor-advocate, was junior counsel for OSB, led by Rory Dunlop KC of 39 Essex St Chambers.

James Packer is a highly regarded public law Director, consistently recognised as "exceptional" and "outstanding" by Chambers and Partners and The Legal 500. He has extensive experience in high-stakes litigation, regularly conducting test cases on matters including access to the courts, unlawful detention, and legal aid refusals. In suitable cases, James also acts as advocate in judicial review matters.

James frequently appears in the Court of Appeal, particularly in costs and procedural challenges.

For advice contact James via email at jamesp@duncanlewis.com or via telephone on 07920077042.

About Duncan Lewis Solicitors

Duncan Lewis Solicitors is one of the UK's largest law firms, providing specialist legal services in immigration, family, public law, and other key practice areas. Based in the City of London with offices nationwide, the firm is recognised for its commitment to excellence, holding the Investors in People Gold Standard Accreditation. Duncan Lewis combines expert legal knowledge with a client-focused approach and strong social responsibility, delivering exceptional support to individuals and families across the country.