Together Against Sizewell C Limited, R (on the application of) v Secretary of State for Energy Security and Net Zero

The identity and scope of a project for habitats assessment are matters of fact and evaluative judgment for the decision-maker, reviewable on conventional public law grounds. Physical or functional connections and cumulative environmental effects do not necessarily make separate developments a single project.

A staged assessment is lawful where a connected second project remains insufficiently defined for meaningful assessment. Its cumulative effects may be assessed when they become sufficiently identifiable, provided the later project cannot proceed without the assessment required by Conservation of Habitats and Species Regulations 2017. A merely hypothetical fall-back proposal need not be assessed.

The appellant sought judicial review of the development consent order for the Sizewell C nuclear power station. The proposed station required a permanent potable water supply, but the source and associated infrastructure had not been determined. The Secretary of State treated the station and the future water-supply arrangements as separate projects. He concluded that the latter would undergo environmental and habitats assessment once sufficiently defined.

Holgate J refused permission to apply for judicial review in [2023] EWHC 1526 (Admin). The Court of Appeal conducted a rolled-up hearing on whether the permanent water supply formed part of the station project and, alternatively, whether their cumulative effects had to be assessed before development consent was granted.

1. Appeal dismissed. Holgate J had correctly refused permission to apply for judicial review. The Secretary of State lawfully treated the power station and the future provision of its permanent potable water supply as separate projects. He was also entitled to defer assessment of the latter project until sufficient information became available.

2. The nature and scope of a project are matters of fact and evaluative judgment for the decision-maker. The court reviews that judgment on conventional Wednesbury grounds. The decision-maker must guard against deliberate project-splitting intended to evade environmental assessment. Subject to that safeguard, connected developments do not necessarily constitute one project merely because their environmental effects may be cumulative.

3. Relevant considerations may include common ownership, functional interdependence, whether each development stands alone and would proceed independently, and whether they undergo simultaneous determination. The factors are neither exhaustive nor rules of law. Their significance and weight depend on the circumstances and are for the decision-maker.

4. The Secretary of State lawfully relied on the absence of any committed water-supply scheme, separate land and responsibilities, distinct statutory processes, and the water undertaker’s obligation to prepare its wider water-resources plan irrespective of the power station. The station could be constructed before a permanent supply was installed. Although water was necessary for operation, there was no inevitable link making the eventual supply method integral to the station project.

5. A staged approach to habitats assessment is legitimate. Under regulation 63 of the Conservation of Habitats and Species Regulations 2017, connected projects may be assessed separately where the second remains insufficiently defined for meaningful assessment. Cumulative effects must be assessed as soon as they become sufficiently identifiable. Deferral was rational because the eventual source, infrastructure and route were unknown, while the later water project could not proceed without its own assessment.

6. The possibility that construction of the station might influence a later assessment did not make deferral unlawful. Regulators were presumed to perform their statutory duties, including any assessment of adverse effects and imperative reasons of overriding public interest. Benefits attributed to an operational station would have to be considered together with its harms.

7. A permanent desalination plant was only an uncommitted fall-back option. It was not included in the application, was not expected to be required and would need separate consent and assessment if later proposed. The Secretary of State therefore had no duty to assess that hypothetical scheme.

1. Court of Appeal (Civil Division): In [2023] EWCA Civ 1517, dismissed the appeal and upheld the refusal of permission to apply for judicial review.
2. High Court, Planning Court: Holgate J refused permission on all pursued grounds after a rolled-up hearing: [2023] EWHC 1526 (Admin).
3. High Court, paper consideration: Kerr J had earlier refused permission because none of the grounds was arguable with a real prospect of success.