Appeal 3352735

The appeal is dismissed.

The site visit was undertaken by a representative of the Inspector whose recommendation is set out below and to which the Inspector has had regard before deciding the appeal.

The revised National Planning Policy Framework (the Framework) was published on 12 December 2024. I have considered the changes and as they are not material to the proposal, further comments were not sought by the parties. I have, however, determined the appeal having regard to the revised Framework.

The main issues are: i) Whether the proposal would be inappropriate development in the Green Belt, having regard to the Framework and any relevant development plan policies; ii) The effect of the proposal on the openness of the Green Belt; and iii) If the proposal would be inappropriate, whether the harm by reason of inappropriateness and any other harm is clearly outweighed by other considerations, so as to amount to the very special circumstances necessary to justify it.

The proposal is for a single storey conservatory extension to [site address] , which is a detached bungalow situated within the London Green Belt. The Framework states, at paragraph 154, that development is inappropriate in the Green Belt unless it meets certain exceptions. One such exception, at paragraph 154 c) is for 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.

The appeal property is a replacement dwelling, which was approved by the Council in 20211. From the evidence before me, there seems to be no dispute between the main parties that the appeal property constitutes the building ‘as it was built originally’, as defined in the Glossary of the Framework. Therefore, [site address] , as it was built originally, is the baseline against which the extension should be considered in the context of the Framework. There is nothing in the Council’s development plan which suggests that a different approach should be taken in the particular local circumstances.

Policy 51 of the Bromley Local Plan (2019) (BLP) states that proposals to extend replacement dwellings will not normally be permitted. However, the appellant argues that this approach is not consistent with the Framework, or with Policy 49 of the BLP and the explanatory text to Policy 51 of the BLP. Whether or not this is the case, Policy 51 of the BLP also states that extensions to dwellings in the Green Belt will only be permitted if a) the net increase in floor area over that of the original dwellinghouse is no more than 10%, and b) their size, siting, materials and design do not harm the visual amenity of the area, and c) the development does not result in a significant detrimental change in the overall form, bulk or character of the original dwellinghouse.

Although the proposal would comply with points b and c as set out above, it would not comply with point a. This is because the net increase in floor area of the extension over that of the original building would be in excess of the 10% limit. Although there are some discrepancies between the actual figures between the Council and Appellant, they both state that there would be an 11% increase in floor area and 9% increase in volume. Consequently, even though the building has not been extended previously and despite the proportions and design of the extension, it would nevertheless conflict with policy 51. However, the 10% criterion is not consistent with the Framework which refers to size of the original building and this could include volume and height etc. Taking these matters together I am satisfied that an 11% increase in the floor space and a 9% increase in the volume and the overall size of the extension would add built form and mass to the original building such that would amount to a disproportionate addition as referenced in the Framework.

The proposal would therefore be inappropriate development in the Green Belt. Paragraph 153 of the Framework states that such development should not be approved except in very special circumstances. 1 Application refence 21/01465/FULL1

Paragraph 142 of the Framework states that the fundamental aim of Green Belt policy is to prevent urban sprawl by keeping land permanently open. The essential characteristics of Green Belts are their openness and their permanence. Openness has a spatial and a visual dimension.

The extension would introduce additional built form and mass to the appeal property. It would therefore materially reduce the openness of the Green Belt from a spatial perspective. The visual effects of the proposal on the openness of the Green Belt would be of a lesser extent. This is because the extension would be confined to the rear of the appeal property, whereby it would have limited visibility from any public vantage points.

Overall, the proposal would cause limited harm to the openness of the Green Belt. However, substantial weight is given to this harm in accordance with paragraph 153 of the Framework. This is in addition to the harm caused by reason of its inappropriateness.

Paragraph 153 of the Framework states that inappropriate development should not be approved except in very special circumstances, and that 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 regard, I have not been provided with any other considerations to weigh as benefits in favour of the development.

The proposal would be inappropriate development in the Green Belt, which is by definition harmful, and it would also have a harmful effect on the openness of the Green Belt, albeit to a limited extent. Substantial weight should be given to the harm to the Green Belt. The totality of the harm would not be clearly outweighed by other considerations and accordingly, very special circumstances do not exist.

Consequently, I conclude that the proposal would conflict with Policy G2 of the London Plan 2021 and Policies 49 and 51 of the BLP. Amongst other matters, these policies state that extensions should not result in disproportionate additions over and above the size of the original building and that development proposals that would harm the Green Belt should be refused except where very special circumstances exist.

The absence of objections from third parties and statutory consultees and indeed the support for the proposal from third parties are not matters which would lead me to a different conclusion on the appeal overall. For the same reasons, the absence of harm in terms of residential amenity does not justify the harm of the proposal to the Green Belt.

Reference is made to the need for the application as permitted development rights have been removed from the property. Even if this is the case, it does not follow that there would be some form of legitimate expectation that some form of extension should be acceptable or that the appeal should be allowed by virtue of the removal of permitted development rights at the appeal property. The appeal has been determined on the basis of the development for which consent is sought and on the basis of the information submitted.

The proposed development would conflict with the development plan as a whole and there are no other considerations, including the provisions of the Framework, which would alter this finding. I therefore recommend that the appeal should be dismissed.

I have considered all the submitted evidence and my representative’s report and on that basis the appeal is dismissed.