Detamu v Secretary of State for the Home Department

An appellate court must itself decide whether an admitted error of law by the primary immigration fact-finder was material. The error is immaterial only if it can be shown that the fact-finder must have reached the same result without it; likelihood is insufficient.

Credibility evidence must be assessed as a whole. An adjudicator may reject an expert report, but must give a reasoned explanation, particularly where the report bears on the core of the account. A peremptory and inconsistent rejection of material expert evidence may undermine the overall credibility assessment and require reconsideration.

The appellant, an Ethiopian national seeking asylum, claimed past detention and torture because of his support for the Oromo Liberation Front. He relied on a report by Dr Trueman concerning the organisation, the plausibility of the account, the time needed to leave Ethiopia and the risk on return.

An adjudicator rejected the appellant's account as not credible. The adjudicator described the expert as biased and unsubstantiated, gave the report no weight, and dismissed the asylum and human-rights claims. The Immigration Appeal Tribunal accepted that this treatment of the report was an error of law, but dismissed the appeal because it considered that the adjudicator would have reached the same conclusion on other grounds.

The central issue was whether that error of law was material.

Appeal allowed and matter remitted to the tribunal for reconsideration. Lord Justice Moses gave the principal judgment. Lord Justice Keene agreed. Lord Justice Pill agreed and gave concurring reasons on the treatment of expert evidence.

1. The Court of Appeal had to determine materiality for itself. It was not confined to asking whether the Immigration Appeal Tribunal could reasonably have concluded that the error was immaterial. Under the approach accepted from [2004] EWCA Civ 1165, an appeal could be dismissed despite an error only if the adjudicator would have been bound to reach the same result without it. An error of law remained an error; the question was whether it affected the outcome.

2. The adjudicator's treatment of Dr Trueman's report was legally erroneous. The report identified the sources supporting its account of the leadership of the Oromo Liberation Front. It also contained qualifications adverse to the appellant's asserted seniority, which contradicted the finding that the expert was biased. The adjudicator could not reject the report comprehensively as biased and unsubstantiated, give it no weight, yet rely on one part of it, without an adequate explanation.

3. The report addressed matters central to the claim, including the appellant's asserted involvement with the organisation, the reasonableness of the period before his departure, and risk on return. Although other adverse credibility findings were independent of the report and might ultimately prove persuasive, the evidence had to be assessed as a whole. The Court could not be confident that a properly directed adjudicator would necessarily have reached the same overall conclusion.

4. Lord Justice Pill added that expert country evidence does not determine an appellant's credibility and may be outweighed by other findings. However, the appellant's account had to be assessed in the context of such material after proper consideration of it. The defective treatment of this material report therefore amounted to a material error of law.

• Court of Appeal (Civil Division) — allowed the appeal and remitted the matter to the tribunal for reconsideration: [2006] EWCA Civ 604.
• Immigration Appeal Tribunal — accepted that the adjudicator's treatment of the expert report was an error of law, but dismissed the appeal on the basis that the error was immaterial.
• Adjudicator — rejected the asylum and human-rights claims on adverse credibility findings.