Ever since E v Home Secretary [2004] EWCA Civ 49, English lawyers have thought errors of fact to be reviewable under a general ground of review. Nowadays, E stands for the proposition that, as a matter of English law, factual mistakes—if they amount to unfairness—constitute a reviewable error of law. I shall show that the Court of Appeal could not have arrived at this decision. The remarks in E to this effect are therefore obiter. I then go on to show that the test in E is incapable of principled application. So the remarks in E proposing a general ground of review should be repudiated.