Appeal 3281908

The appeal is dismissed.

The main issues are: • whether the proposal would amount to inappropriate development in the Green Belt, • the effect of the proposed extension on the openness of the Green Belt, and • if the proposal would be inappropriate development, whether the harm by reason of inappropriateness, and any other harm, is clearly outweighed by other considerations, so as to amount to very special circumstances to justify it.

The site is within the small settlement of [site address] which is over-washed by the Green Belt. Policy CP8 of the Wycombe District Local Plan (2019)(LP) states that the Council will protect the Green Belt from inappropriate development. Paragraph 137 of the National Planning Policy Framework (the Framework) identifies that the fundamental aim of the Green Belt is to prevent urban sprawl and keep land permanently open. Paragraph 149 establishes that new development would be inappropriate unless it meets a listed exception. Exception (c) allows for “the extension or alteration of a building provided it does not result in disproportionate additions over and above the size of the original building”.

The phrase ‘disproportionate’ is not defined by the Framework. This is therefore ultimately a matter for the decision maker, with much depending on the individual circumstances of the proposal. However, a conclusion on this matter cannot be arrived at purely on a mathematical calculation as a single factor as the test is primarily an objective one based on size, as referenced by the Framework.

Policy DM43 of the LP identifies extensions to dwellings in the Green Belt will only be permitted if it would satisfy various volumetric calculations, depending on the volume of the dwelling. The Council has determined that the volume of the original dwelling was 260 cubic metres. Consequently, the policy deems that an extension of up to 50% of the original volume of the dwelling could be allowed. The cumulative effect of several extensions would need to be taken into account when considering the overall effect of any extension. The policy also requires the proposed development to not exceed the volumes of neighbouring dwellings.

The language used in policy DM43 varies slightly from that of the Framework in reference to volume rather than size and in differentiating between smaller and larger dwellings. Nevertheless, I am satisfied that the policy provides a useful starting point for consideration of extensions that might be deemed to be disproportionate. This approach also provides developers with a clear indication of the Council’s expectations within the district’s Green Belt in this regard.

The dwelling has been extended in the past. The Council’s planning history, and my own observations on site, illustrate that the house has been subject to two storey and single storey rear extensions. It is undisputed between parties that these have resulted in a 54% increase in volume. These have therefore added a substantial proportion of additional built form to the size of the original dwelling.

The proposed extension is relatively small and would only result in an increase in volume of around 7.5% in comparison to the original dwelling. However, this addition would, in combination with existing extensions, result in a total increase in volume of around 61.5%. Policy DM43 also requires the surrounding context of the site to be taken into account. This shows that the extended dwelling would be greater than the size of both adjacent neighbouring dwellings. Consequently, the local pattern of development does not offer a compelling reason to patently deviate from the Council’s general approach to this matter. Given these points and my own observations, the proposed extension in combination with the existing extensions, would amount to a disproportionate addition to the size of the original dwelling.

As it has not been demonstrated that the proposal would meet any of the exceptions listed in Paragraph 149 of the Framework, it would amount to inappropriate development which is, by definition, harmful to the Green Belt.

The openness of the Green Belt has both spatial and visual dimensions. It is an open textured concept that requires a range of factors to be taken into account when considering the effect of a proposal on openness. The appellant has drawn my attention to a number of Judgements that I have taken into account in my assessment of openness. I especially note the appellant’s reference to the Goodman Judgement1 where “visual perception [is] a factor which may reduce the spatial harm from the effect of development on the openness of the Green Belt”.

The proposed extension would add a relatively small single-storey addition to the rear of the dwelling. This would be located between the rear two-storey extension of the appeal dwelling and the rear extensions of the neighbouring semi-detached dwelling. The appeal site includes a long rear garden. The garden is partially enclosed by boundary vegetation to its sides. It is on a slight gradient with the rear boundary at a slightly higher elevation than the appeal dwelling. The open countryside is evident beyond the rear boundary of the site. The proposal would be visually integrated, and largely indivisible, from views of the existing pattern of development. As a result, the visual effect of the proposal on the openness of the Green Belt would be negligible.

However, spatially, the proposal would increase the footprint of the dwelling and thus increase its size. Paragraph 134 of the Framework outlines the five purposes of including land within the Green Belt. Whilst limited in size, the proposal would represent encroachment into the countryside. Accordingly, although the proposal would result in no visual harm, it would result in moderate spatial harm. In this matter, I am unconvinced that the spatial harm is outweighed by the absence of visual harm, resulting in moderate harm to the openness of the Green Belt.

I am cognisant that the proposal would be in keeping with the design of the existing dwelling and the surrounding area. Furthermore, the proposed extension would result in an increased kitchen providing lifestyle benefits to the occupiers of the dwelling.

The appellant draws on the conclusions made by an appeal decision2 for an equestrian building in Hatfield. This fell within paragraph 149(b) of the Framework for development associated with outdoor sport and outdoor recreation. As such, considerations of whether the development was inappropriate development was a matter that turned fully on its effect on the openness of the Green Belt. Accordingly, the proposal and its Green Belt impact was materially different to the matters related to this scheme. As a result, that decision is of limited weight in my consideration of this appeal.

Paragraphs 147 and 148 of the Framework set out the general presumption against inappropriate development within the Green Belt. They explain that such development should not be approved except in very special circumstances. Very special circumstances to justify inappropriate development will not exist unless the potential harm to the Green Belt, by reason of inappropriateness, and any other harm, is clearly outweighed by other considerations.

I have concluded that the appeal scheme would be inappropriate development that would, by definition, harm the Green Belt. I have also concluded that the proposal would result in moderate harm to the openness of the Green Belt. 1 [name] (UK) v SSCLG and [name] [2017] EWHC 947 (Admin) 2 Planning Appeal reference: APP/C1950/W/3227024 Paragraph 148 of the Framework requires substantial weight to be given to any harm to the Green Belt.

On the other hand, the other considerations I have identified, including the acceptable design of the scheme, are of limited weight in favour of the proposal. As such, the harm to the Green Belt is not clearly outweighed by the other considerations identified. Therefore, the very special circumstances necessary to justify the development do not exist. Accordingly, the proposal fails to adhere to the local and national Green Belt policies I have already outlined.

The proposal would be inappropriate development, harming the Green Belt and in conflict with the development plan when taken as a whole. Therefore, for the reasons given, I conclude that the appeal should not succeed.