Appeal 3332523

The appeal is dismissed.

The National Planning Policy Framework (the Framework) was revised in December 2023. As the changes do not materially affect the main issues in this case, the parties have not been invited to make further comments. References to the Framework in this decision pertain to the most recent version.

The main issues are: a) whether the proposal would be inappropriate development in the Green Belt having regard to the Framework and any relevant development plan policies, b) the effect of the proposal on the openness of the Green Belt, and c) whether any harm by reason of inappropriateness, and any other harm, would be clearly outweighed by other considerations, so as to amount to the very special circumstances required to justify the proposal.

Paragraph 154 of the Framework states that the construction of new buildings is inappropriate in the Green Belt, albeit with a limited number of exceptions. This includes, at paragraph 154(c), the extension or alteration of a building provided that it does not result in disproportionate additions over and above the size of the original building. Saved policy GB13 of the Chiltern District Local Plan 1997 (CLP) sets out that extensions to existing dwellings will be permitted if they are subordinate to the size and scale of the original dwelling.

There is no definition as to what represents a disproportionate addition over and above the size of the original building, nor is there one in the CLP for what a subordinate extension would be. However, ‘original’ is defined in the CLP and means, in relation to a building existing on 1 July 1948, as existing on that date and, in relation to a building built on or after 1 July 1948, as so built.

The existing dwelling is a detached property, in a chalet bungalow style, that is set on a generous and largely enclosed plot. The proposal is for a front extension providing an enclosed porch, store and downstairs toilet and shower room. It is nominated by the Council that the existing property has been enlarged, in floorspace terms, by around 70% over the original dwelling and the appellant does not disagree with this.

I do not have specific details on the appearance or volume of the original dwelling. It was, however, apparent to me at the site visit that there had been alterations and extensions constructed at the property due to the use of slightly different materials and design vernaculars to various elements of the building. The host property has already been substantially extended and the proposal, albeit small in size, would introduce additional development and an overall volumetric increase well above the size of the original property. Due to the previous increases in floorspace and volume at the property, further development must result in a disproportionate addition over and above the original building that would not be subordinate to the original dwelling.

I therefore conclude the extension would represent a disproportionate addition. Consequently, the proposal would be inappropriate development in the Green Belt as defined by the Framework. Moreover, it would not be subordinate to the original dwelling. The development thus conflicts with policies GB2 and GB13 of the CLP and provisions of the Framework.

A fundamental aim of Green Belt policy, as set out by the Framework, is to prevent urban sprawl by keeping land permanently open. Openness is, in effect, the absence of development and it has both visual and spatial dimensions.

The small scale of the extension, its position which does not project forward of the existing garage and discreet setting within an enclosed plot means that the proposed development would have negligible impacts on the visual aspects of the Green Belt. However, the cumulative increase in floor area, volume and scale would conflict with the spatial dimensions of the Green Belt.

Consequently, for the reasons given above, the development would not preserve the openness of the Green Belt. As such, the proposal would conflict with the fundamental aim of the Green Belt, as set out in the Framework, to keep land permanently open.

The proposed extension is small and would provide an accessible downstairs toilet and shower room. The occupants of the dwelling do not presently need this facility and it would only be required by visiting friends and relatives. I do, nevertheless, recognise the benefits of providing accessible facilities to all members of the community and future-proofing the property for residents.

Paragraph 153 of the Framework states that, when considering any planning application, substantial weight must be given to any harm to the Green Belt. Very special circumstances will not exist unless the potential harm to the Green Belt by reason of inappropriateness, and any other harm resulting from the proposal, is clearly outweighed by other considerations. In this instance, I acknowledge that the level of harm would be limited. The proposal would be inappropriate development which would be harmful. This harm carries substantial weight by definition.

The other considerations, in particular providing an accessible downstairs toilet and shower, do carry significant weight. However, this must clearly outweigh the substantial weight that I must give to the harm to the Green Belt, by reason of inappropriateness and effect on openness. This is a high hurdle for any development proposal to overcome. I conclude that the very special circumstances necessary to justify the development, which clearly outweigh the inherent harm to the Green Belt, do not exist.

The proposal is therefore inappropriate development in the Green Belt contrary to GB2 and GB13 of the CLP and provisions of the Framework.

For the reasons given above the proposal conflicts with the development plan and the material considerations do not indicate that the appeal should be decided other than in accordance with it. The appeal is dismissed.