Swire, R (On the Application Of) v Secretary of State for Housing, Communities and Local Government

At the screening stage, a decision-maker may consider proposed mitigation, but must first make an informed judgment about the likely environmental effects of the development and the availability and effectiveness of the mitigation. Planning conditions cannot be treated as a complete answer where the nature, extent or remediation of the environmental risk remains materially uncertain. The decision-maker must not assume that future investigations and remedial works will have a satisfactory outcome. The precautionary principle means that material doubt will generally favour requiring an environmental impact assessment. A screening decision is unlawful where it relies on conditions to eliminate potentially significant effects without sufficient evidence to assess whether those conditions can do so effectively.

The claimant sought judicial review of a direction made by the Secretary of State under the Town and Country Planning (Environmental Impact Assessment) Regulations 2017. The direction concluded that an outline proposal for up to 20 dwellings at a former animal-rendering site in a Kent Downs Area of Outstanding Natural Beauty was not EIA development.

The site had previously been used to render cattle infected with BSE. The available contamination reports did not address that use, prion contamination, or the hazards and methods of remediation associated with it. The Secretary of State relied on proposed planning conditions requiring further investigation and remediation. The central issue was whether he could conclude that significant environmental effects were unlikely by relying on those future measures.

1. The claim succeeded. The Secretary of State’s direction that the proposal was not EIA development was quashed.
2. Under regulation 5 of the Town and Country Planning (Environmental Impact Assessment) Regulations 2017, the screening authority had to take account of the relevant information and Schedule 3 criteria and make an informed judgment whether the development was likely to have significant effects on the environment.
3. Proposed remedial or ameliorative measures may be considered. However, the authority cannot treat planning conditions as a surrogate for the EIA process or assume that future investigations and works will produce a satisfactory result. The relevant questions include the nature and extent of the risk, the uncertainties in the proposed remediation, the effects during remediation, and the likely final outcome.
4. The evidence concerning BSE-related contamination was inadequate. The reports submitted with the planning application did not address the site’s former use for BSE-infected carcass rendering. There was no expert evidence identifying the nature or extent of any prion contamination, the risks to future residents, or effective methods of detection and remediation.
5. The proposed conditions required future investigation and a remediation method statement, but no party knew what remediation would be required. The Secretary of State therefore could not make an informed judgment that the measures would safeguard the environment or human health. His conclusion assumed that the future works would be successful, repeating the legal error identified in Gillespie v First Secretary of State [2002] EWCA Civ 400.
6. The precautionary principle, reflected in the EIA regime, meant that material doubt should generally be resolved in favour of an EIA. The possibility that issues might later be investigated through planning conditions did not cure the failure to assess them within the EIA framework, including its environmental statement and public consultation.
7. The court did not need to decide the alternative grounds based on failure to take account of a material consideration and irrationality. The error was substantive rather than merely technical, and the direction was quashed.

First-instance judicial review in the High Court (Administrative Court). The judgment does not state any subsequent appellate decision.