Substation Action Save East Suffolk Ltd, R (on the application of) v Secretary of State for Energy Security and Net Zero & Ors

A policy requiring flood risk from all sources to be considered does not necessarily extend a sequential test framed by reference to fluvial flood zones to surface water flooding. Unless the policy prescribes a particular method, the treatment of surface water risk is a matter of planning judgment. Location and mitigation may be considered together.

Environmental information must be examined before development consent is granted, but examination may show that information does not affect the assessment of the proposed development. The cumulative effects of a separate future project may lawfully be deferred where inadequate information prevents a reliable assessment.

The Secretary of State granted development consent for two offshore wind farms and associated onshore substations and National Grid infrastructure at Friston, Suffolk. A local residents’ company challenged the decisions under Planning Act 2008.

Lang J dismissed the claim in [2022] EWHC3177 (ADMIN). The claimant appealed on two grounds. It argued that flood policies required proof that no reasonably available site had a lower surface water flood risk. It also argued that environmental information about possible extensions of the National Grid substation for the future Nautilus and Eurolink projects had unlawfully been excluded from the assessment of cumulative effects.

Appeal dismissed.

1. The sequential test in the relevant national policies was framed by reference to Flood Zones 1, 2 and 3. Those zones concern the probability of fluvial flooding. The policies did not require an applicant, whenever surface water risk existed, to demonstrate that no reasonably available site had a lower surface water flood risk.

2. Surface water risk nevertheless had to be considered throughout the planning process. The decision-maker had to be satisfied that a sequential approach had been applied at site level to minimise risk and direct vulnerable uses towards areas of lowest risk. The method of achieving that aim was a matter of planning judgment, reviewable on ordinary public law grounds. On the facts, the applicants could address the policy aim through a combination of the location of infrastructure and mitigation. The Secretary of State’s conclusion was neither irrational nor otherwise unlawful.

3. The judge had understood that parts of the infrastructure remained in areas of medium or high surface water flood risk. Her references to location and mitigation reflected the two means by which that risk was addressed. In any event, any factual error by the judge would have been immaterial because the Secretary of State made no such error.

4. Under regulation 21(1) of the Infrastructure Planning (Environmental Impact Assessment) Regulations 2017, the Secretary of State had to examine the environmental information and take the result of that examination into account when reaching a reasoned conclusion on the significant effects of the proposed development. Examination could establish that particular information did not affect that conclusion.

5. The Extension Appraisal concerned possible future alteration of the substation to accommodate separate potential projects. It was examined, but insufficient information existed for a reliable cumulative impact assessment. The Secretary of State could lawfully defer that assessment. It was unnecessary to decide whether Schedule 4 paragraph 5(e) extended beyond existing or approved projects to future or potential projects.

Lewis LJ gave the judgment. William Davis and Coulson LJJ agreed.

1. Court of Appeal (Civil Division): The appeal was dismissed in [2024] EWCA Civ 12. The court upheld the interpretation and application of the flood-risk policies and the decision that cumulative assessment of the future projects could be deferred.
2. High Court, Administrative Court, Planning Court: Lang J dismissed the judicial review claim in [2022] EWHC3177 (ADMIN).