R v North Norfolk District Council and another

Article 6(3) of the Habitats Directive does not require a formal screening procedure equivalent to environmental impact assessment screening. It requires an appropriate assessment where a risk of significant effects on a protected site cannot be excluded.

Environmental impact assessment screening should occur early. A lawful negative opinion may be reviewed when new facts emerge, but a legally defective opinion cannot be cured by conducting an equivalent assessment outside the prescribed framework. Mitigation may be considered at screening, although material doubt should generally be resolved in favour of assessment.

A procedural breach does not invariably require the planning permission to be quashed. Relief may be refused where the court, without placing the burden on the claimant, concludes that the decision would have been unchanged, effective public participation occurred and no substantial prejudice resulted.

R v North Norfolk District Council and another concerned planning permission for silos, a lorry park and associated facilities near the River Wensum, a Special Area of Conservation. The proposed drainage system created a potential risk of polluted run-off. Following further investigations, revised mitigation and consultation with Natural England and the Environment Agency, the council decided that neither environmental impact assessment nor appropriate assessment was required and granted conditional permission.

A Deputy High Court Judge allowed the claim for judicial review and quashed the permission. The Court of Appeal reversed that decision in [2013] EWCA Civ 1657, holding that the council could rationally conclude that the development would not have significant adverse effects.

The issues before the Supreme Court concerned the timing of environmental impact assessment and Habitats assessment decisions, the permissible consideration of mitigation measures, and the availability of discretionary refusal of relief where a procedural irregularity had occurred.

1. Disposition. Lord Carnwath delivered the judgment, with which Lord Neuberger, Lord Mance, Lord Clarke and Lord Toulson agreed. The appeal was dismissed. The council had committed a procedural irregularity under the environmental impact assessment regime, but the court refused to quash the planning permission.

2. The Habitats Directive and the Conservation of Habitats and Species Regulations 2010 prescribe no formal screening process equivalent to environmental impact assessment screening. Where the position is not obvious, the competent authority must decide whether the trigger for appropriate assessment is met. That informal threshold decision need not occur at a separately prescribed stage. An appropriate assessment need take no particular form, but it must investigate the matter to the high standard required to satisfy the authority that the project will not adversely affect the protected site's integrity. Absolute certainty is unattainable; the ultimate conclusion is a judgment for the competent authority.

3. By the final decision, further information, revised mitigation and expert consultation had satisfied the council that any material risk to the protected site had been eliminated. Nothing further was identified that would have been required to meet the standard in Waddenzee, Case C-127/02. The failure to address the article 6(3) trigger earlier therefore did not invalidate the final Habitats decision.

4. Environmental impact assessment screening should ordinarily occur early. A lawful negative screening opinion may require review when material facts later emerge. A legally defective negative opinion, or a failure to screen, cannot instead be cured by carrying out an analogous process outside the prescribed framework. Classification depends on the characteristics and effects of the proposal as presented for screening, rather than measures developed subsequently to address those effects. The initial opinion was defective and the proposal should have been treated as development requiring assessment.

5. Mitigation is not invariably excluded from environmental impact assessment screening. Its permissible use depends on the circumstances. The prescribed process nevertheless contemplates that measures preventing, reducing or offsetting significant effects will be presented in an environmental statement and exposed to public participation. Where potentially significant impacts depend on measures that remain uncertain or insufficiently developed, the precautionary principle generally requires assessment. The later resolution of those uncertainties did not retrospectively cure the failure.

6. Following Walton v Scottish Ministers [2012] UKSC 44 and applying Gemeinde Altrip v Land Rheinland-Pfalz Case C-72/12, the court retained discretion to refuse relief. It could conclude from the evidence, without imposing the burden on the claimant, that the decision would not have differed without the defect. The environmental issue was neither novel nor especially complex; statutory consultees examined the measures through several revisions; and the public participated fully. No substantial prejudice was shown. Relief and a reference to the Court of Justice were therefore refused.

• United Kingdom Supreme Court: Dismissed the appeal unanimously, while holding that an environmental impact assessment procedural irregularity had occurred. It exercised its discretion to refuse relief.
• Court of Appeal: Allowed the council's appeal and reversed the order quashing the planning permission. It held that the council could rationally decide that neither environmental impact assessment nor appropriate assessment was required: [2013] EWCA Civ 1657.
• High Court: A Deputy High Court Judge allowed the judicial review claim and quashed the planning permission because the council's conclusions were considered inconsistent with the precautionary monitoring conditions. A separate challenge to Natural England's response was dismissed and was not appealed.