Royal Borough of Kensington And Chelsea v The Secretary of State for Communities And Local Government

On a challenge under Town and Country Planning Act 1990, an error of fact warrants quashing where it played a material, though not necessarily decisive, part in the inspector’s reasoning and caused unfairness. The court must read the decision letter as a whole and construe it flexibly. It must not substitute its own planning judgment for that of the inspector.

An inspector may make a qualitative planning judgment that recent planning permissions indicate some further housing over-supply, even where the monitoring evidence records those permissions, provided that the inspector has not added a duplicated numerical figure. The court’s discretion not to quash is not exercised where materiality prevents it from concluding that the same decision would have been reached without the error.

The local planning authority applied under section 288 of the Town and Country Planning Act 1990 to quash an inspector’s decision allowing an appeal against the authority’s failure to determine a planning application.

The application concerned the amalgamation of four flats into one family dwelling. The authority alleged two factual errors in the inspector’s assessment of five-year housing land supply: double-counting vacant units returning to use, and double-counting recent planning permissions. The Secretary of State conceded the first ground. The second defendant contested both the claim and the materiality of the first error.

1. The application under section 288 was allowed and the Secretary of State’s decision was quashed.
2. The court accepted that the inspector had made a mistake of fact by deducting vacant units returning to use from the housing requirement while including them in the supply. The first three criteria identified in E v Secretary of State for the Home Department [2004] EWCA Civ 49 were satisfied.
3. The decisive question was whether the mistake played a material, not necessarily decisive, part in the inspector’s reasoning. A decision letter must be read fairly and as a whole. The inspector’s references to the available information and the evidence indicating that the authority was on target included the erroneous calculation. Housing land supply was therefore a material factor in the planning balance, and the error caused unfairness.
4. Ground 2 failed. The inspector had not added a quantified figure for recent planning permissions. He had made a qualitative planning judgment, based partly on the relationship between approvals and completions in the monitoring report, that there would be at least some further over-supply. That judgment was open to him.
5. The court declined to exercise its discretion not to quash. Although a later-discovered error in the monitoring report was relevant, it had little bearing on discretion because it was discovered after the inspector’s decision. Since the court could not say that the inspector would have reached the same conclusion without the material error, the decision could not stand.