In Watt, R (on the application of) v London Borough of Hackney & Anor [2016] EWHC 1978 (Admin), the High Court quashed the grant of permission for a mixed-use development likely to adversely affect sunlight reaching adjacent open land used by the neighbouring school for children’s play. The application had been considered on the basis the redevelopment of the vacant site would have enhanced the character and appearance of the conservation area. The authority relied on a daylighting report addressing the extent of reduction in daylight to the play land at different times of year. A claim for judicial review was made on several grounds. An independent assessment – carried out after the claim had received permission to proceed – identified flaws in the original report, exaggerating the existing levels of daylight and so understating (by a third) the effect of the new scheme on the play land.
Gilbart J admitted the new report as part of a new ground alleging an error of fact. The defendant authority countered the new evidence, but – crucially – did not object to its admission. In finding an error of fact that justified quashing the permission, Gilbart J held that the criteria in E v Home Secretary [2004] EWCA Civ 49 were made out: firstly, a factual error which created a misleading picturel; secondly, the fact was ‘established’, in the sense of being uncontentious and objectively verifiable; thirdly, neither the appellant (nor his advisers) were responsible; and finally, the error played a material part in the reasoning (on the basis that it was impossible to say that had not done so, applying Simplex GE (Holdings) Ltd v Secretary of State for the Environment (1989) 57 P&CR 306).
Two points are worth noting. The second criterion was made out despite the fact that there was some disagreement on the effect of the error on the relevant thresholds. The fourth (materiality) criterion was held to be engaged despite the fact that the error may not have been decisive in the overall decision, given that the daylight reaching the play area was above the relevant policy threshold with the correct analysis (just less far above than the original assessment had, wrongly, suggested). The judgement confirms the risk that faulty technical work creates for planning decisions, even where the error itself is not decisive.
