Ian Galloway, R (on the application of) v Durham County Council

A planning permission must be interpreted by its natural and ordinary meaning in its statutory and factual context. Where a condition requires development in strict accordance with approved plans, that ordinarily requires rigid adherence. A later details-approval condition does not permit substantive departure unless the permission clearly provides for it.

For a solar farm, the question whether the development may exceed the statutory capacity threshold is distinct from the question of planning impact. Where the approved panel layout appears substantially larger than necessary for a lawful generating capacity, that may be an obviously material planning consideration. Failure to address it can render the permission unlawful. A non-material amendment cannot cure that underlying unlawfulness.

The claimant challenged Durham County Council’s grant of full planning permission for a solar farm near Burnhope and a subsequent non-material amendment. The challenges concerned the statutory capacity threshold for nationally significant infrastructure projects, the interpretation of conditions requiring strict accordance with approved plans, and whether later details approval permitted changes to the panel layout.

The claimant also argued that the Council had failed to consider whether the approved layout contained substantially more panels and blue-covered land than required for a lawful solar farm below the 50MW threshold. The central issues were whether the permission was unlawful and whether the subsequent amendment could preserve or cure it.

1. Strict accordance. Planning Condition 4 required the development to be carried out in strict accordance with the approved plans. The word “strict” meant rigid adherence. Condition 12 required precise details of above-ground structures to be submitted before commencement, but did not authorise departures from the approved plans. The approved plans’ descriptions as preliminary or typical, and supporting application documents, could not rewrite the express condition.
2. Panel identity and capacity. The electronic file metadata referring to Trina 685 Wp panels did not form part of the substantive content of the approved panel plan. The planning permission could therefore be built with panels of the same dimensions but lower power. Further, the Combined-Panels Method was a recognised conventional method of measuring capacity, but was not established as the only legally correct method. The first line of challenge therefore failed.
3. Material consideration. The statutory 50MW threshold, the recognised methods of measuring solar-farm capacity, the substantial increase in panel rows and the resulting blue and green footprint made it obviously material to ask whether the permission approved more panels and a larger covered area than required for a lawful 50MW-class solar farm. The Council’s failure to address that question was unreasonable in the public-law sense and could have made a difference.
4. Non-material amendment. The amendment purporting to clarify that Condition 12 permitted departure from the approved plans was based on an erroneous interpretation of the permission. The amendment capping export capacity at 49.9MW AC was likewise vitiated by the mistaken premise that it merely stated an existing restriction. In any event, the amendment could not cure the original failure to consider an obviously material consideration.
5. The original planning permission and the non-material amendment were quashed. The matters were remitted to the Planning Committee to consider whether the permission approved more panels over a larger area than required to produce a 49.9MW solar farm. The claimant’s two judicial review claims were allowed, with costs of £32,000 and £9,000 respectively.

This was a first-instance judicial review decision. The court allowed both claims and remitted the relevant decision-making to the Council’s Planning Committee.