Heath and Hampstead Society, R (on the application of) v Camden

Whether a replacement dwelling in Metropolitan Open Land or the Green Belt is “materially larger” than the dwelling it replaces is primarily an objective question of actual physical size. The relevant dimensions may include floor space, footprint, volume, height and width. Perceived size may assist in a marginal case, but visual impact cannot replace the required comparison of size.

A materially larger replacement is inappropriate development and is harmful by definition. Its reduced visibility may be relevant when deciding whether very special circumstances outweigh that harm, but it cannot make the development appropriate. Metropolitan Open Land receives the same protection as the Green Belt, whether it is publicly accessible or privately owned.

The claimant society sought judicial review of the defendant local planning authority’s grant of permission for a replacement dwelling on a private backland site designated as Metropolitan Open Land. Depending on the measurement used, the proposed house would be between two and four times the size of the existing dwelling.

The applicable planning policy treated a replacement dwelling as appropriate development only if it was not materially larger than the dwelling it replaced. No very special circumstances were advanced. The officer’s report and oral advice nevertheless concentrated on the limited visibility and perceived visual impact of the additional building.

The central issues were whether “materially larger” was principally a comparison of physical size, whether visual considerations could affect that assessment, and whether the committee had been lawfully advised.

1. The application for judicial review was allowed and the planning permission was quashed. The replacement dwelling was plainly materially larger than the existing dwelling. Its floor space, footprint and volume produced increases of between approximately two and four times. No reasonable assessment applying the correct policy test could conclude otherwise.

2. The inquiry under paragraph 3.6 of PPG 2 was primarily an objective comparison of physical size. The most relevant dimension depended on the circumstances and might include floor space, footprint, volume, height or width. Surrey Homes Limited v Secretary of State for Environment, Transport and the Regions was correctly decided in recognising that bulk, height, mass and prominence could also be relevant. In most cases, however, floor space would be the starting point and might be the most important criterion.

3. Qualitative considerations could assist where the measured increase was marginal. They could not displace physical measurements or substitute a test based on whether the new dwelling was more visually intrusive. Paragraph 3.6 concerned the size of the replacement dwelling, while visual amenity was addressed separately. Reduced visibility might support a case that very special circumstances outweighed the harm caused by inappropriate development, but it could not make a materially larger replacement appropriate development.

4. Metropolitan Open Land received the same protection as the Green Belt. Its essential characteristic was openness. That protection applied equally to designated private land without public access. Loss of unbuilt land was intrinsically harmful to the policy objective, irrespective of whether the additional development was visible from public vantage points.

5. An officer’s report must be read fairly, as a whole and in accordance with its general reasoning rather than construed as a statutory instrument, applying South Somerset District Council v Secretary of State for Environment [1993] 1 PLR 80. Even on that approach, the report and oral advice failed to address the threshold question. They used visibility and demonstrable visual harm in place of the required comparison of actual size. Members who approved the proposal adopted that erroneous reasoning.

6. The defendant was ordered to pay the claimant’s costs, agreed at £18,000 including VAT where chargeable. Permission to appeal was refused.

The defendant granted the interested parties planning permission on 23 January 2006. On the claimant’s first-instance application for judicial review, the High Court allowed the application and quashed that permission. The High Court refused permission to appeal.