Camilla Swire, R (on the application of) v Canterbury City Council

On an application for subsequent consent for EIA development, the local planning authority must decide whether the environmental information already available is adequate to assess significant environmental effects. That assessment is case-specific and may be challenged only on public law grounds. A court will not infer a failure to consider the issue where the officers’ report addresses it directly. Material produced after the challenged decision cannot ordinarily establish that the decision was unlawful when made. “Salami slicing” occurs where a single project is divided into separate parts so as to circumvent environmental assessment requirements; it does not arise where the whole development was assessed at the outline-permission stage and the continuing adequacy of the information was considered when subsequent consent was granted.

The claimant challenged Canterbury City Council’s decision of 19 October 2022 to approve reserved matters for a spine road forming part of a development for which outline planning permission had been granted in 2018. The development was EIA development and had been supported by an Environmental Statement.

The claimant alleged that the Council had failed to consider whether changes to anticipated infrastructure required a further assessment under the Town and Country Planning (Environmental Impact Assessment) Regulations 2017, and that the reserved-matters application involved impermissible “salami slicing”. A previous permission decision had been dismissed, and permission for this judicial review was considered by Lang J on the papers before renewal. The central issue was whether either ground was reasonably arguable.

1. Permission refused. Neither ground was reasonably arguable.
2. Regulation 3 of the Town and Country Planning (Environmental Impact Assessment) Regulations 2017 prohibits the grant of planning permission or subsequent consent for EIA development unless the required environmental assessment has been carried out. The reserved-matters approval was a subsequent consent for that purpose.
3. Under regulation 9(2) and (3), the local planning authority must decide whether the environmental information already before it is adequate to assess the development’s significant environmental effects. The question is for the authority, subject to public law challenge, and must be determined case by case. The Council had considered the alleged infrastructure changes when the outline permission was granted, including through sensitivity analysis, and no condition made the development dependent on the disputed infrastructure.
4. The Council had directly addressed the need for a further Environmental Statement in the officers’ report. There was therefore no proper basis for inferring that the issue had been ignored. Additional material filed after the decision could not affect its rationality when made. In any event, that material treated the changes as insignificant and proposed mitigation only as a contingency.
5. The “salami slicing” ground also failed. The whole development, including the spine road, had been assessed on the basis of a full Environmental Statement at the outline stage. The continuing adequacy of the environmental information had been considered at the reserved-matters stage. Dividing the project for assessment purposes had not occurred.

The claim was a first-instance application for permission to bring judicial review proceedings. Permission had previously been refused on the papers by Lang J and was renewed orally before Mr Justice Chamberlain. Permission was refused.