Wingfield, R (On the Application Of) v Canterbury City Council

Whether related developments constitute one project for environmental impact assessment is a matter of planning judgment, reviewable on ordinary public law grounds. Relevant considerations include common ownership, simultaneous determination, functional interdependence and whether each proposal is independently justified and capable of proceeding alone.

Overlapping or cumulative environmental effects do not themselves make separate developments a single project. Once the project has lawfully been identified, assessment of its cumulative effects with other projects satisfies the statutory requirement. An appropriate assessment under the habitats regime must use the best scientific knowledge and dispel reasonable scientific doubt, but its adequacy ultimately remains a matter for the competent authority, subject to rationality review.

A local resident sought judicial review of the Council’s grant of outline planning permission for a mixed-use development on the former Chislet Colliery site. An adjoining site at Hoplands Farm had separately received outline permission for residential and associated development.

The principal issue was whether the two developments had to be treated as a single project under the Town and Country Planning (Environmental Impact Assessment) Regulations 2011 and Directive 2011/92/EU, rather than as separate projects whose cumulative effects were assessed. The claimant also renewed an application for permission to challenge the Council’s habitats assessment and sought to raise additional, unpleaded objections to the environmental assessments.

1. The claim on Ground 1 was dismissed. Identifying the project for environmental impact assessment was a matter of judgment for the competent authority, subject to Wednesbury rationality and other public law grounds. Relevant indicators included common ownership, simultaneous determination, functional interdependence and whether each development was a stand-alone proposal justified on its own merits.

2. The Chislet and Hoplands developments were separate projects. They had different owners and promoters, separate planning histories, access and drainage arrangements, and no functional interdependence. Each would proceed independently of the other. Their adjacency and overlapping environmental effects were relevant but not determinative, because distinct projects may generate cumulative effects requiring assessment.

3. The case did not involve “salami slicing” to evade environmental assessment. Both developments underwent full environmental impact assessment, including consideration of their cumulative effects. Once the scope of each project had lawfully been identified, the law required assessment of cumulative effects; it did not require the developments to be assessed as one project.

4. The Council rationally considered the Chislet proposal to be the relevant project. Nothing at the screening or scoping stages reasonably required an inquiry into whether it formed a single project with Hoplands. When the point was later raised, the Council expressly considered and lawfully rejected it. The environmental statement, read fairly and with its supplements, met the requirements of Schedule 4 and provided sufficient environmental information for the Council’s decision under regulation 3(4).

5. Permission on Ground 2 was refused. Although an early draft of the habitats assessment contained weaknesses, the material errors were corrected before adoption. Natural England concurred with the assessment for Chislet. Its reservations about Hoplands concerned different and less-developed mitigation evidence, so the Council could rely on its Chislet advice without explaining the different response in the separate application.

6. Permission to add the unpleaded challenges under Grounds 1 and 2 was also refused. New judicial review grounds required a proper amendment application, a clearly drafted pleading and, where late, an application for an extension of time. The proposed grounds were in any event unarguable. Mitigation may be considered in a substantive habitats or environmental impact assessment, notwithstanding People over Wind [2018] PTSR 1668, which concerned screening under the habitats regime.

This was a first-instance judicial review claim. Thornton J had granted permission on Ground 1 and refused permission on Grounds 2 and 3. The claimant renewed Ground 2 for determination at the substantive hearing, but did not pursue Ground 3. Lang J dismissed Ground 1 and refused permission on Ground 2 and on the proposed additional grounds.