Heath & Hampstead Society, R (on the application of) v Vlachos & Ors

For a replacement dwelling on Metropolitan Open Land, the requirement that it be not materially larger than the dwelling replaced is a threshold test directed primarily to relative physical size and scale. It does not permit a planning authority to substitute a broad assessment of visual impact on openness.

Floor space will normally be the starting point, but footprint, volume, height, bulk, massing and siting may bear on whether a marginal increase is material. Those considerations cannot, however, make a very substantial increase in the size of a replacement dwelling immaterial merely because its visual effect is limited.

Camden Council granted planning permission for demolition of a modest two-storey house on a backland site within Metropolitan Open Land and for its replacement with a substantially larger dwelling. Although the proposed building was no higher, its floor space, volume and footprint would all increase substantially.

The Heath & Hampstead Society successfully challenged the permission in the Administrative Court. Sullivan J quashed it. The owners and Camden appealed to the Court of Appeal in [2008] EWCA Civ 193.

The central issue was whether the Metropolitan Open Land policy test that a replacement dwelling be “not materially larger” required principally a comparison of physical size, or instead a broader judgment about the proposal’s impact on the interests protected by the policy.

1. Appeal dismissed. The court upheld Sullivan J’s order quashing the permission. The council had misunderstood and misapplied the Metropolitan Open Land policy.

2. The relevant provision of PPG 2 was a threshold categorisation of whether a replacement dwelling was appropriate development. It was distinct from the later assessment of harm and other planning considerations. The words “not materially larger” therefore focused principally on the relative size of the existing and proposed dwellings, rather than their relative visual impact.

3. Size was not confined to floor space. In line with the accepted point in Surrey Homes Ltd v Secretary of State for Environment, bulk, height, mass, prominence and site disposition could mean that even a small numerical increase was material. That flexibility allowed planning judgment and common sense, but it did not create a broad “no greater impact” test. PPG 2 used such broader language elsewhere when that was what it intended.

4. The policy’s reference to limited replacement development, read with the requirement that extensions be proportionate to the original building, confirmed that the new dwelling should be similar in scale to that replaced. A local authority could not reasonably conclude that a building more than twice as large in floor space, volume and footprint was not materially larger merely because much of the increase would be screened or below ground.

5. The officer’s report was to be read fairly and not as legislation. Nevertheless, it never addressed the critical “materially larger” question. Its focus on limited visual and openness effects could not cure the legal error in applying the threshold policy.

• Court of Appeal (Civil Division): In [2008] EWCA Civ 193, dismissed the owners’ and Camden Council’s appeals and upheld the quashing of the planning permission.
• Administrative Court: Sullivan J allowed the Society’s judicial review claim and quashed Camden Council’s grant of planning permission.