Factual and Procedural Background
This opinion concerns a statutory review under section 113 of the Planning and Compulsory Purchase Act 2004 ("the 2004 Act") challenging part of a joint local development plan known as the Joint Core Strategy 2010-2030 ("JCS"), prepared jointly by two local planning authorities, referred to here as Local Authority A and Local Authority B. The JCS forms part of the statutory development plan for the relevant district areas, including a national park area.
The challenge was brought by a third local planning authority ("Plaintiff") whose district contains a Special Area of Conservation ("SAC") designated under the Habitats Directive for its vulnerable lowland heath habitat. The SAC lies within the Plaintiff's district area, with two major roads passing near or through it. The Plaintiff contends that the JCS failed to lawfully consider the potential in-combination environmental effects of planned development on the SAC, particularly in combination with another core strategy adopted by the Plaintiff ("Plaintiff's Core Strategy").
The Secretary of State for Communities and Local Government ("Defendant 1") was involved as the examining Inspector had recommended adoption of the JCS. Local Authority A adopted the JCS on 11th May 2016 and Local Authority B adopted it on 23rd June 2016. The Plaintiff issued proceedings on 4th August 2016 seeking to quash specific spatial policies within the JCS.
Legal Issues Presented
- Whether Local Authority A and Local Authority B acted unlawfully by concluding, based on expert advice, that the JCS would not likely have a significant effect on the SAC in combination with the Plaintiff's Core Strategy.
- Whether the examining Inspector failed to have regard to the Plaintiff’s relevant representations regarding potential effects of planned development on the SAC.
- Whether the challenge is in time, given the joint adoption of the JCS by two authorities on different dates.
- Whether the legal advice and methodology relied upon, particularly the use of a 1,000 Annual Average Daily Traffic (AADT) threshold as a screening criterion for significant effects, was legally sound and properly applied in the Habitats Regulations Assessment (HRA).
- The proper interpretation and application of Article 6(3) of the Habitats Directive and Regulation 102 of the Habitats Regulations in relation to in-combination effects at the scoping and appropriate assessment stages.
Arguments of the Parties
Appellant's Arguments
- The Habitats Directive and Regulations require consideration of in-combination effects of plans. The JCS’s HRA failed to properly aggregate traffic data from the JCS and the Plaintiff's Core Strategy, resulting in an unlawful conclusion that no significant effect would arise.
- The expert advice from Natural England, which underpinned the HRA, was legally flawed because it asserted the 1,000 AADT threshold covered in-combination effects without proper reasoning or scientific basis.
- The examining Inspector did not err in addressing the Plaintiff’s representations, but the fundamental legal error lies in the flawed advice and consequent assessment.
- The challenge is timely as the relevant date for the six-week limitation period is the adoption date by Local Authority B, the last adopting authority.
Respondents' Arguments
- The HRA properly considered in-combination effects based on expert advice from Natural England, which was consistent with the Plaintiff's own approach and established practice.
- The 1,000 AADT threshold is robust, precautionary, and effectively covers any likely in-combination effects, making any additional aggregation unnecessary at the scoping stage.
- The court should be slow to second-guess expert opinion where no contrary expert evidence is presented, and the decision-making process was not irrational or unlawful.
- The challenge to Local Authority A’s adoption is out of time; the challenge to Local Authority B’s adoption is in time but should be limited to that authority’s administrative area.
Table of Precedents Cited
| Precedent |
Rule or Principle Cited For |
Application by the Court |
| Blyth Valley BC v Persimmon Homes (North East) Ltd [2008] EWCA Civ 861 |
Application of conventional administrative law principles to challenges under section 113 of the 2004 Act. |
Confirmed that challenges must be assessed on the basis of whether the development plan document is within power and complies with procedural requirements. |
| R. (Champion) v North Norfolk DC [2015] 1 WLR 3710 |
Consideration of likely significant effects as a trigger for appropriate assessment under Article 6(3) of the Habitats Directive. |
Supported the principle that an appropriate assessment is required where significant effects cannot be excluded. |
| Ashdown Forest Economic Development LLP v Wealden District Council [2015] EWCA Civ 681 |
Requirement to consider in-combination effects and the weight to be given to expert advice from statutory consultees. |
Affirmed that expert advice should be given considerable weight but is not binding if cogent reasons exist to depart from it. |
| R (Mynydd y Gwynt) v Secretary of State for Business Energy and Industrial Strategy [2016] EWHC 2581 |
Clarification of the standard of certainty required for appropriate assessment under Article 6(3). |
Confirmed that a strict precautionary approach and evaluative judgments are required. |
| Waddenzee Case (Case C-127/02) [2004] ECR-1 7405 |
Interpretation of "likely significant effects" and the necessity of appropriate assessment. |
Provided foundational guidance on the precautionary principle and the need to exclude reasonable scientific doubt. |
| Sweetman and others v An Bord Pleanála (Case C-258/11) [2014] PTSR 1092 |
Requirement for assessments to be complete, precise and capable of removing reasonable scientific doubt. |
Emphasized the strictness and thoroughness required in appropriate assessments. |
| Smyth v Secretary of State for Communities and Local Government [2015] EWCA Civ 174 |
Application of the precautionary principle and distinction between legal requirements and evaluative judgments. |
Highlighted the need for strict precaution but acknowledged evaluative discretion. |
| R (oao DLA Delivery Ltd) v Lewes DC and Newick Parish Council [2017] EWCA Civ 58 |
Assessment of procedural compliance with Article 6(3) in neighbourhood planning. |
Supported the notion that mitigation measures are relevant and that the challenge must be grounded in sound assessment. |
| R (oao Mott) v Environment Agency [2016] 1 WLR 4388 |
Deference to expert opinion on technical matters in judicial review. |
Warned courts against substituting their own judgment for tenable expert opinion. |
| Tesco Stores Ltd v Dundee City Council [2012] UKSC 13 |
Objective interpretation of policy statements. |
Confirmed that policy interpretation is a matter of law for the courts. |
| R (on the application of the Manchester Ship Canal Company Ltd) v Environment Agency [2013] EWCA Civ 542 |
Judicial role in policy interpretation. |
Confirmed courts’ role in interpreting policy objectively. |
Court's Reasoning and Analysis
The court first addressed the timeliness of the challenge, concluding that the six-week limitation period runs separately from each local planning authority’s adoption date. The challenge was out of time against Local Authority A but in time against Local Authority B, as the latter adopted the plan later.
Turning to the substantive issue, the court acknowledged that Article 6(3) of the Habitats Directive and the Habitats Regulations require an appropriate assessment where a plan is likely to have a significant effect on a protected site, either alone or in combination with other plans.
The court examined the Habitats Regulations Assessment (HRA) and the expert advice from Natural England, which relied on a 1,000 AADT threshold as a screening tool for likely significant effects. The court found that the HRA expressly stated that in-combination effects must be considered, but in practice, the assessment did not aggregate the traffic contributions from the JCS and the Plaintiff’s Core Strategy.
The court rejected the argument that the DMRB guidance justified excluding cumulative effects at the scoping stage, holding that in-combination effects are relevant at both scoping and appropriate assessment stages. The court found the Natural England advice legally flawed because it asserted that the 1,000 AADT threshold sufficiently covered in-combination effects without adequate scientific or methodological explanation.
The court highlighted that the sum of the traffic flows from the two plans exceeded the threshold, which should have triggered an appropriate assessment. It found the failure to aggregate these figures and properly assess cumulative impact to be a Wednesbury unreasonable error infecting the HRA and the decision-making process.
The court also considered post-decision evidence submitted by Natural England and expert consultants, which reinforced that the advice was erroneous in law. The court held that decision-makers should have made further inquiry of Natural England regarding the advice, and the failure to do so was irrational.
Regarding the scope of relief, the court reasoned that the JCS operates as separate development plan documents for each adopting authority’s area. Therefore, the court’s power to quash is limited to the administrative area of the adopting authority against whom the challenge is in time. The court declined to quash the JCS for Local Authority A’s area as the challenge was out of time.
The court further analyzed the housing and traffic data for Local Authority B’s area and concluded that while the additional traffic attributable to Local Authority B alone did not exceed the threshold, the total combined traffic from all relevant plans did. The court emphasized that Article 6(3) requires a holistic in-combination assessment without fine legalistic distinctions between contributions from different authorities.
In conclusion, the court found the HRA and the adoption of the JCS by Local Authority B to be legally flawed due to reliance on erroneous expert advice and failure to properly assess in-combination effects, warranting quashing of the relevant spatial policies for that authority’s area.
Holding and Implications
The court held that the challenge to the Joint Core Strategy was out of time in relation to Local Authority A’s adoption but in time in relation to Local Authority B’s adoption.
The court found that the Habitats Regulations Assessment was legally flawed due to reliance on erroneous expert advice from Natural England, which failed to properly assess in-combination effects of traffic on the Special Area of Conservation.
As a result, the court quashed policies SP1 and SP2 of the Joint Core Strategy to the extent they form part of the development plan for Local Authority B’s administrative area.
The decision requires Natural England to reconsider its advice and calls for clarification of the relevant governmental guidance (DMRB). The ruling limits the remedial effect of the challenge geographically and emphasizes the necessity for proper cumulative environmental assessments in development planning.
No new precedent beyond the application of existing principles on appropriate assessment, administrative law, and statutory interpretation was established. The ruling primarily affects the parties by requiring reconsideration of the relevant policies within Local Authority B’s area.