Dacorum Borough Council, R (on the application of) v Secretary of State for Communities and Local Government & Anor

Under PPG2, the references to an existing dwelling and to the original building address different matters. The former concerns the structure being extended or replaced. The latter concerns the size against which an extension is measured and may refer to an earlier building that has since been replaced. The interpretation must also accord with any applicable local planning policy and explanatory text. A planning inspector commits an error of law if he misunderstands relevant authorities or leaves material policy text out of account. The court may intervene where the policy wording is not capable of bearing the interpretation adopted.

The Council challenged an inspector’s decision concerning a conservatory at a replacement dwelling in the Green Belt. The inspector treated the replacement building as the relevant original building and concluded that the conservatory fell within the permitted percentage increase under PPG2 and Policy 22 of the Dacorum Local Plan.

The Council brought an application under sections 288 and 289 of the Town and Country Planning Act 1990. The central issues were the meaning of “original building” in PPG2, paragraphs 3.4 and 3.6, the relationship between PPG2 and Policy 22, and whether the inspector had considered the explanatory text to Policy 22.

1. The Council’s application was upheld. The inspector’s decision granting permission for the conservatory was legally flawed.

2. PPG2 paragraphs 3.4 and 3.6 use two different concepts. Paragraph 3.4 concerns the structure involved in a proposed extension, alteration or replacement. Paragraph 3.6 concerns the size of that structure and requires an extension to be assessed against the size of the original building. The deliberate contrast between “existing” and italicised “original” supported that construction.

3. “Original building” could therefore refer to a building which had previously occupied the site, even though it had been demolished and replaced. The possibility of missing plans did not outweigh the policy concern that successive replacement dwellings could otherwise be enlarged cumulatively.

4. The inspector misunderstood Ascot Wood Ltd v Secretary of State for the Environment, Transport and the Regions [2000] PLCR 265 and Brentwood Borough Council v Secretary of State for the Environment, Transport and the Regions. Neither decision had finally determined the meaning of PPG2. The latter decision had turned substantially on the wording of the particular local policy under consideration.

5. The explanatory text to Policy 22 was a material consideration. It defined the “original dwelling” by reference to the dwelling existing on 1 July 1948, or the first dwelling built thereafter. The inspector failed to address that text and incorrectly treated Policy 22 as having the same meaning as PPG2. That omission and misinterpretation constituted errors of law.

6. The court applied the approach in R v Derbyshire County Council, ex parte Woods [1997] JPL 958: the court determines what policy wording is capable of meaning, while the decision-maker retains planning judgment within those legal limits.

The matter arose from an inspector’s decision dated 2 June 2008 allowing the appeal in part under section 174 of the Town and Country Planning Act 1990 and granting permission for the conservatory. The Secretary of State consented to judgment. The High Court upheld the Council’s challenge.