High Court quashes planning refusal in Greystoke CB v Secretary of State over highways policy error

The High Court has quashed a planning inspector's decision to dismiss an appeal against the refusal of planning permission for a 140,000 square metre employment scheme near Banbury, finding the inspector had misapplied national policy on when development may lawfully be refused on highways grounds.

Mr Justice Coppel heard the statutory review brought by Greystoke CB Limited under section 288 of the Town and Country Planning Act 1990, challenging an inspector's decision dismissing its appeal against Cherwell District Council's refusal of outline permission for warehousing and ancillary offices on agricultural land near junction 11 of the M40. Following a nine day inquiry, the inspector found in the developer's favour on the two specific thresholds set out in paragraph 116 of the National Planning Policy Framework, concluding the scheme would not cause an unacceptable impact on highway safety at the M40 junction, nor would its residual cumulative impact on the wider road network, including congestion at Hennef Way and Southam Road in Banbury, be severe. However, the inspector went on to find that the developer had not demonstrated adequate mitigation for the congestion impacts that would arise, contrary to the separate mitigation requirement in paragraph 115 of the Framework, and treated this as the most significant factor weighing against the scheme when striking the overall planning balance, according it substantial weight ahead of locational, landscape and heritage harms.

Greystoke's central argument was that the inspector, having found the paragraph 116 thresholds unmet, was required to carry that conclusion through to the planning balance stage, since paragraph 116 makes clear that permission should not be refused on highways grounds absent an unacceptable safety impact or severe residual congestion. The Secretary of State resisted this, arguing the refusal was not "on highways grounds" because it rested on a broader combination of factors including locational and landscape harm, and that requiring paragraph 116 to be revisited at the balancing stage would improperly constrain decision-makers from giving appropriate weight to non-severe traffic impacts that remained genuinely material.

Mr Justice Coppel rejected the Secretary of State's narrow reading of the phrase "on highways grounds", holding it could not sensibly be confined to cases where highways impacts formed the sole basis for refusal, since planning decisions are almost invariably the product of multiple factors weighed together. He held that, at minimum, paragraph 116 is engaged wherever a decision-maker treats highways impacts as the principal or main reason for refusal and the planning balance would likely have been struck differently absent those impacts. Applying that test, the judge found the inspector had plainly treated highways impacts as the dominant consideration, noting that it was the only factor accorded substantial weight, and that the inspector had himself indicated his conclusion would remain unchanged even under the more favourable "tilted balance" applicable to out of date locational policies, a statement the judge read as confirming the centrality of highways concerns to the outcome. The decision was accordingly unlawful for failing to weigh paragraph 116 into the ultimate balancing exercise, notwithstanding that the inspector remained free, subject to a rational planning justification, to depart from the Framework's guidance.

A further ground concerning alleged procedural unfairness was left undetermined as academic, since the matter would in any event return to the inspector for reconsideration with the benefit of fresh submissions from both parties. The court also upheld a separate ground that the inspector had failed to factor the scheme's biodiversity net gain, found to be 23 per cent for habitats and 10 per cent for hedgerows and tree lines, into the planning balance at all, a material consideration the Secretary of State accepted, for the purposes of the case, ought to have been taken into account.

The decision letter was quashed and the appeal remitted to the Secretary of State for redetermination.