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

Factual and Procedural Background

The Plaintiff sought judicial review to quash a planning permission granted by the Defendant to the Interested Parties on 23 January 2006. The permission related to the demolition of an existing part 1, part 2-storey dwellinghouse known as The Garden House, located in the Vale of Health, London, and the erection of a new part 2, part 3-storey dwellinghouse with associated landscaping. The site is designated as Metropolitan Open Land (MOL) and lies within the Hampstead and Highgate Ridge Area of Special Character and the Hampstead Conservation Area. The Defendant’s Development and Control Sub-committee granted the permission despite concerns about the size increase of the replacement dwelling.

The planning permission was challenged on the basis that the replacement dwelling was materially larger than the existing dwelling, contrary to policy governing development in MOL, which affords protection equivalent to Green Belt land. The case raised questions about the proper interpretation and application of planning policies concerning the size and appropriateness of replacement dwellings within MOL.

Legal Issues Presented

1. Whether the planning permission for the replacement dwelling was lawful given the policy that replacement dwellings on Metropolitan Open Land must not be "materially larger" than the existing dwelling.
2. Whether the assessment of whether a replacement dwelling is "materially larger" should be a purely quantitative comparison of physical dimensions or also include qualitative factors such as visual impact.
3. Whether the Defendant’s planning officer and committee properly applied the relevant policies, particularly the test in paragraph 3.6 of Planning Policy Guidance 2 (PPG 2) and Policy N1 of the Unitary Development Plan (UDP).

Arguments of the Parties

Appellant's Arguments

• The assessment of whether a replacement dwelling is "materially larger" should be based on a straightforward mathematical comparison of dimensions such as footprint, floor space, volume, height, and width.
• Visual impact and qualitative considerations are irrelevant at this threshold stage and only become relevant once it is established that the replacement is not materially larger.
• If the replacement dwelling is materially larger, very special circumstances must be demonstrated to justify permission.
• Even if qualitative factors can be considered, they cannot override clear quantitative increases; a replacement dwelling twice or more the size of the existing must be materially larger regardless of visual impact.
• The planning officer’s report and advice to the committee wrongly focused on visual impact rather than size, leading to an erroneous conclusion.

Respondent's Arguments (Defendant and Interested Parties)

• The question of whether a replacement dwelling is "materially larger" is a matter of planning judgment, not a purely mathematical calculation.
• Qualitative factors such as bulk, height, mass, prominence, and visual impact are relevant to the assessment of materiality.
• Neither Policy N1 in the UDP nor paragraph 3.6 of PPG 2 prescribe a strict mathematical formula for "materially larger".
• The decision in Surrey Homes Limited v Secretary of State supports the view that the assessment includes qualitative considerations related to openness and visual impact.
• The officer’s report and committee properly considered the relevant policies and reached a conclusion reasonably open to them.

Table of Precedents Cited

Court's Reasoning and Analysis

The court began by affirming that Metropolitan Open Land (MOL) is to be afforded the same protection as Green Belt land, including the presumption against inappropriate development. The threshold question was whether the replacement dwelling was "materially larger" than the existing dwelling, a test derived from paragraph 3.6 of PPG 2 and Policy N1 of the Revised UDP.

The court rejected the Plaintiff’s submission that the assessment should be solely quantitative but agreed that the test is primarily an objective one based on physical size (floor space, footprint, volume, height, width). Qualitative factors such as visual impact and bulk may inform the assessment, especially in marginal cases, but cannot override clear and substantial increases in size.

Applying this reasoning to the facts, the court found that the replacement dwelling was between two and four times larger than the existing dwelling by various measurements, including floor space, footprint, and volume. Such an increase was plainly "material".

The court criticized the planning officer’s report and advice to the committee for focusing on visual impact and concealment rather than the material size increase. The officer’s approach risked incremental erosion of MOL openness by permitting developments that were materially larger but visually less intrusive.

The court also noted that the committee members who opposed the permission recognized the error in the approach taken, but the majority adopted the flawed officer’s report as their reason for granting permission.

In conclusion, the court held that the Defendant’s decision failed to apply the correct threshold test and that the grant of planning permission was unlawful.

Holding and Implications

The court ALLOWED the application for judicial review and QUASHED the planning permission granted by the Defendant.

The direct effect is that the planning permission for the replacement dwelling is invalidated. The decision underscores the importance of applying the correct legal test for "materially larger" in the context of development on Metropolitan Open Land and Green Belt. The court emphasized that the threshold question is principally one of objective size rather than visual impact, preventing a policy approach that might permit incremental encroachments on protected land due to concealment or design factors.

The court awarded costs to the Plaintiff summarily assessed at £18,000 including VAT.