KM v Secretary of State for the Home Department

In an Article 8 proportionality appeal, an immigration tribunal must make its own decision on proportionality. It cannot merely ask whether the Secretary of State’s decision was one that no reasonable Secretary of State could make. An earlier error in applying that Wednesbury approach does not require remittal where the tribunal separately addressed proportionality in its own reasoning and reached a conclusion open to it. Materiality is assessed by the effect of the error on the determination when made, not by later facts or knowledge.

KM appealed against an Immigration Appeal Tribunal determination concerning her proposed removal to Zimbabwe, relying on the proportionality of the interference with her Article 8 rights. The Tribunal had applied the approach then reflected in M (Croatia), but had also addressed proportionality independently. Following the Court of Appeal’s decision in ZT, the principal issues were no longer pursued. The remaining question was whether the Tribunal’s erroneous Wednesbury approach required remittal despite its separate reasoning on proportionality.

1. The Court dismissed the appeal in KM. The other appeal before the court, Mando, was also dismissed because it raised substantially the same issues as ZT.
2. The Immigration Appeal Tribunal had initially treated Article 8 proportionality as turning on whether the Secretary of State’s decision was one which no reasonable Secretary of State could have made. That approach was erroneous in light of Huang. The tribunal’s task was to make its own decision on proportionality.
3. The error did not determine the outcome. The opening language of paragraph 35 showed that the Tribunal was consciously departing from its earlier reasoning and addressing proportionality from its own perspective. It considered the relationship between the Article 3 and Article 8 conclusions and gave a properly reasoned conclusion which was open to it.
4. An error of law is material by reference to its effect on the Tribunal’s determination when that determination was made. The assessment is not made by asking how the Tribunal might decide the case in the light of later facts or later knowledge about conditions in Zimbabwe.

Since the Tribunal would have reached the same result had Huang been before it, the error was immaterial. There were no grounds for remittal.

• Court of Appeal (Civil Division): dismissed KM’s appeal, holding that the Immigration Appeal Tribunal’s legal error was immaterial.
• Immigration Appeal Tribunal: dismissed KM’s appeal concerning proposed removal to Zimbabwe. The decision’s citation was not stated in the judgment.