Canterbury City Council v Secretary of State for Housing, Communities and Local Government

At the screening stage under article 6(3) of the Habitats Directive, mitigation measures intended to avoid or reduce harm to a protected site must be disregarded. If significant effects cannot be excluded on objective information without those measures, an appropriate assessment is required. A court may nevertheless withhold relief for the resulting error of law only where it is certain that the decision would necessarily have been the same. That assessment must not involve the court in remaking the planning judgment. The seriousness of the procedural breach and any loss of public participation are relevant. A planning decision-maker may assess uncertain infrastructure outcomes as risks and weigh them in the planning balance. Previous appeal decisions are material considerations, but an inspector may depart from them if adequate reasons are given.

Two section 288 challenges concerned grants of planning permission for residential development at Strode Farm, Canterbury, and Broden Stables, Crondall. In both cases, the decision-makers screened out appropriate assessment by taking account of mitigation measures directed to recreational pressure on European sites. The Secretary of State conceded that this approach was unlawful following People Over Wind v Coillte Teoranta C-323/17.

The Canterbury challenge also alleged irrationality in granting permission without an enforceable mechanism securing highway infrastructure. The Crondall challenge raised issues concerning the weight given to countryside-protection policies, previous appeal decisions and an emerging local plan. The central questions were whether relief should be withheld despite the admitted error and whether the additional planning-law grounds succeeded.

1. Appropriate assessment. The approach in R (Hart District Council) v Secretary of State for Communities and Local Government [2008] EWHC 1204 (Admin) and Smyth v Secretary of State for Communities and Local Government [2015] EWCA Civ 174, which permitted mitigation to be considered at screening, was no longer good law following People Over Wind v Coillte Teoranta C-323/17. Mitigation measures must be disregarded at screening. Both decisions therefore contained an error of law.
2. Relief. The court retained a discretion under section 288 of the Town and Country Planning Act 1990. Relief could be withheld only if the court was satisfied that the decision would necessarily have been the same. The court could not re-enter the forbidden territory of remaking the planning balance. The seriousness of the procedural defect and whether the public had been deprived of access to information or participation were relevant.
3. Canterbury. The environmental material contained a detailed assessment of the potentially affected European sites, had been extensively consulted upon, and the conclusions were uncontroversial. The court was certain that the Secretary of State would have reached the same decision after an appropriate assessment. The irrationality challenge concerning the Kent BRIS failed: assessing the uncertain prospect of infrastructure delivery and weighing it against other considerations was a lawful planning judgment.
4. Crondall. The Inspector was entitled to treat the first limb of policy RUR2 as out of date and to attach moderate weight to it. He adequately explained his departure from R (on the application of Wynn-Williams) v Secretary of State for Communities and Local Government [2014] EWHC 3374 (Admin) and his treatment of the later Netherhouse Copse appeal. The emerging local plan was properly given very limited weight. However, unresolved objections concerning the effectiveness and location of the SANG mitigation meant that the court could not be certain that the decision would have been the same without the errors. The Crondall decision was quashed.

These were first-instance section 288 challenges to planning decisions by the Secretary of State and a planning inspector. The Canterbury claim was dismissed. The Crondall decision was quashed.