Colney Heath Parish Council v Secretary of State for Communities & Local Government & Ors

A planning decision must address every principal controversial issue raised by the evidence. This includes a distinct issue concerning the development’s effect on flood risk outside the site, even where conditions may mitigate that risk. The decision-maker must evaluate the evidence and explain the conclusion reached; the existence of conditions does not remove that duty. A failure to address such an issue may justify quashing the decision where there is a real possibility that proper consideration would have made a difference. Reasons may also be required so that unsuccessful objectors understand the approach taken and its implications for future applications.

The Parish Council applied under section 288 of the Town and Country Planning Act 1990 to quash an Inspector’s decision allowing planning permission for a gypsy family’s residential use of land at Nuckies Farm. The Inspector addressed flood risk to occupants of the site and imposed conditions relating to flooding.

The Local Planning Authority had, however, produced Environment Agency evidence that the development could reduce floodplain storage, obstruct flood flows and increase flooding risks to surrounding property. The central issue was whether the Inspector had failed to take that off-site flooding issue into account and to give adequate reasons for his decision.

1. The claim succeeded. The Inspector’s decision was quashed.
2. Off-site flooding was a principal controversial issue. The evidence before the inquiry expressly raised whether the development would reduce floodplain storage, obstruct flood flows and increase flood risk to others. The Inspector therefore had to take the issue into account and address it expressly in the decision letter.
3. The issue did not cease to be controversial merely because the Environment Agency witness might have accepted in cross-examination that conditions could mitigate the risk. It was for the Inspector, who had heard the evidence, to determine the effect of that evidence and whether the development remained unacceptable despite conditions.
4. The references in the decision letter to general risk to life, raised mobile homes, personal safety, occupation of the site and conditions did not address the specific question whether the development would create an unacceptable risk of flooding outside the site. Conditions 6 to 10 did not cure that omission.
5. Planning decisions need not address every evidential detail or read like examination papers. They must nevertheless convey the real sense and basic reasoning of the decision on each principal important controversial issue.
6. There was a real possibility that proper consideration of off-site flooding would have made a difference to the outcome. The Parish Council therefore suffered sufficient prejudice. The issue was also important because unsuccessful objectors needed to understand the approach that might affect future applications.