E v Secretary of State for the Home Department [2004] EWCA Civ 49
E is not a planning case on its facts, but it is a major public-law authority with particular relevance to planning because it recognises material mistake of fact giving rise to unfairness as a separate ground of challenge.
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- Neutral citation
- [2004] EWCA Civ 49; [2004] QB 1044; [2004] 2 WLR 1351
- Court
- Court of Appeal (Civil Division)
- Judgment date
- 2nd February 2004
- Judge
- The Master of the Rolls, Mantell LJ and Carnwath LJ
- Case number
- C1/2003/1394 & C1/2003/2203
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Mistake of fact can amount to unfairness
The Court of Appeal held that a mistake about an existing fact can, in appropriate circumstances, give rise to unfairness and therefore amount to an error of law.
The court identified four ordinary requirements: the mistake must concern an existing fact or the availability of evidence; the correct position must be objectively verifiable and uncontentious; the claimant must not be responsible for the mistake; and the mistake must have played a material, although not necessarily decisive, part in the reasoning.
Why the judgment matters in planning
Lord Justice Carnwath specifically examined planning cases when developing the principle. He noted that, although planning inquiries are adversarial, the planning authority and the Secretary of State share a public interest in ensuring that development control proceeds on the correct factual basis.
The judgment discusses Simplex GE (Holdings) Ltd v Secretary of State for the Environment in detail as an important example of a planning decision invalidated by a material factual mistake.
Read the judgment
The full judgment is available from Find Case Law: E v Secretary of State for the Home Department [2004] EWCA Civ 49.
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E v Home Secretary Case Law Page Updated: 11th September 2026