Appeal 3375346

The appeal is dismissed.

The appellant advises that listed building consent (LBC) was granted for the appeal scheme on 19 September 2025.1 However, full details of the consented scheme, including the approved plans are not before me. I acknowledge that there are some inconsistencies in the Council’s decision making regarding this scheme and that the Council raises no objections to the proposal on heritage grounds. Despite the Council granting LBC for the proposal, the Council considers that the proposed roof extension would harm the character and appearance of the building. As the appeal property is a [name] listed building, I am required to exercise my own judgment on the heritage impacts and have a statutory duty under section 66(1) of the Planning (Listed Buildings and Conservation Areas) Act 1990 (the Act) to have special regard to the desirability of preserving the listed building or its setting or any features of special architectural or historic interest which it possesses. I am also not bound by the Council’s decision to grant LBC.

The main issues are: i) whether the proposed development would be inappropriate development in the Green Belt having regard to the National Planning Policy Framework (the Framework) and any relevant development plan policies; ii) the effect of the proposed development on the openness of the Green Belt; 1 Application ref: 25/00976/LBC iii) whether the proposal would preserve a [name] listed building known as ‘ [site address] ’ (Ref: 1064357) and any of the features of special architectural or historic interest that it possesses; and, iv) if the proposal is inappropriate development, would the harm by reason of inappropriateness, and any other harm, be clearly outweighed by other considerations as to amount to the very special circumstances required to justify the development.

The appeal property is a large, detached dwelling which is located within the Green Belt. It is two storeys high, with attic and basement. The appeal property lies within a rural location and is set within extensive and well landscaped grounds.

The fundamental aim of Green Belt policy is to prevent urban sprawl by keeping land permanently open. Inappropriate development is, by definition, harmful to the Green Belt and should not be approved except in very special circumstances. Substantial weight should be given to any harm, and 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.

The Framework sets out that development in the Green Belt is inappropriate, unless it falls within one of the listed exceptions. It is common ground between both main parties that exception 154c) is applicable to this appeal. This exception relates to ‘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.’

Policy 51 of the Bromley Local Plan (the Local Plan) January 2019 provides criteria for assessing proportionality. It states that extensions to a dwelling within the Green Belt will only be permitted where among other things, the net increase in floor area over that of the original dwellinghouse is no more than 10%. Policy 51 defines the ‘original dwelling’ to mean as it existed on 1 July 1948, or, if constructed after 1 July 1948, as it was built originally. This is consistent with the definition given in Annex 2 of the Framework.

The supporting text to Policy 51 explains that the objective of this policy is to ensure that there is no incremental harm to the Green Belt by excessive extensions to dwellings, which may jeopardise the open nature of the Green Belt. This is broadly consistent with the aims of the Framework

I appreciate that the proposed single storey extension would be subservient in terms of its height and overall size and would not appear overbearing in relation to the host dwelling. The proposed roof extension would also be sited between the existing valleys of the roof and would be set well back, which helps to minimise its visual impact. However, the proposal would result in a 20% increase in floorspace when compared to the original dwelling, which would considerably exceed the 10% limit set out within Policy 51 of the Local Plan. I appreciate that floor space is not the sole determining factor when assessing or measuring proportionality. The Framework refers to ‘size’ in relation to the original building, which can reasonably be interpreted to include volume, height, external dimensions, footprint or floorspace.

The proposal would also result in a 30% increase in footprint and 14% increase in volume of the dwelling, which is already of a substantial size. The proposal would result in additional bulk and massing to the rear of the building and at roof level. While the rear extension is set in from the side elevations of the building, its depth (including the glazed link) would be deeper than either of the existing ranges. Although the proposed swimming pool is a below ground structure, the proposed pool and area of hardstanding would spread development further across the site, which would have an urbanising effect on the Green Belt. Cumulatively, I find that the proposal would result in disproportionate additions over and above the size of the original dwelling. Accordingly, the proposal would be inappropriate development in the Green Belt and would conflict with Policies 49 and 51 of the Local Plan and Policy G2 of the London Plan March 2021 (the London Plan). These policies among other things seek to protect the Green Belt from inappropriate development and requires that any extension within the Green Belt does not result in a disproportionate addition over and above the size of the original building.

Openness is an essential characteristic of the Green Belt that has visual as well as spatial aspects. The appeal property is located within a spacious plot and is well screened from the public realm by the existing boundary treatment and soft landscaping. Given the size and siting of the proposal, any views from the public realm would be very limited. Views of the proposal would be available from the adjacent land, but these would be private views only. As a result, the harm to the visual openness of the Green Belt would be limited. In addition, the proposal by virtue of the additional built form would result in a loss of spatial openness to the Green Belt.

For the reasons given above, I conclude that the proposal would result in a harmful loss of openness to the Green Belt; albeit this harm would be limited given the scale of the proposal. Consequently, the proposal would conflict with the fundamental aim of Green Belt policy set out in the Framework, which is to keep land permanently open.

[site address] is a [name] listed building, which is constructed of red brick, with burnt headers and is finished in Flemish bond. It consists of two parallel ranges. The front range dates back to the late 17th century. The rear range is a later addition and according to the date stone, dates back to 1839. The building has a tiled roof and a distinctive double pile roof formation. The building features traditional, timber, sash windows.

Based on the evidence before me and my site visit, I find that the special interest of the listed building insofar as is relevant to this appeal derives from its historic and architectural interest as an illustration of domestic architecture from the early 17th century. The building’s pleasing architectural form, its double pile roof formation and use of traditional materials make important contributions in these regards.

The Council’s second reason for refusal relates solely to the proposed roof extension. Based on the evidence before me and my site visit, I have no reason to reach a contrary conclusion to the Council on the other aspects of the scheme and consider that they would preserve the special interest of the listed building.

The appeal property has a distinctive double pile roof formation, which contributes towards its special interest. While the proposed roof extension would be set back from the edge of the roof, the proposal would partially fill the gap between the double pile roof, which would harmfully disrupt the form of the roof and erode the building’s special interest. While the proposal would feature conservation grade rooflights, the contemporary nature of the roof extension and the use of modern materials would harmfully discord with the traditional materials and historic character of the host building. The proposal would also result in the loss of historic fabric, which further adds to this harm.

While the proposed roof extension would be largely concealed from public views by the existing built form and surrounding landscaping. Listed buildings are safeguarded for their inherent architectural and historic interest irrespective of whether or not public views of the building can be gained.

For the reasons given above, I find that the proposal would fail to preserve the special interest of the listed building. I give this harm considerable importance and weight in the planning balance of this appeal.

Paragraph 212 of the Framework advises that when considering the impact of development on the significance of designated heritage assets, great weight should be given to the asset’s conservation. Paragraph 213 states that significance can be harmed or lost through the alteration or destruction of those assets, or from development within its setting and that any such harm should require clear and convincing justification. Given the nature and extent of the proposal, I find the harm to the special interest of the listed building to be less than substantial and at the lower end of the scale. However, this should not be equated with a less than substantial objection and is of considerable importance and weight. Paragraph 215 of the Framework advises that this harm should be weighed against the public benefits of the proposal, including where appropriate, securing the asset’s optimum viable use.

The proposal would result in investment into the property, which would have a small economic benefit, which carries limited weight in favour of the proposal as a public benefit. The appellant argues that preserving and upgrading the building’s fabric carries significant weight as a public benefit. I appreciate that the proposal would improve the thermal efficiency of the building. However, given that the proposal relates to a single property, any environmental benefits which would flow to the public at large are likely to be minimal. Furthermore, there is no compelling evidence before me that any works to preserve or upgrade the building’s fabric are solely dependent on the provision of the proposed extensions. In this case, I find that the benefits which would accrue would primarily be of a private nature.

While the proposal would improve the functionality and living accommodation for the appellant, the provision of additional accommodation and the change to the internal layout are purely private benefits. Although the evidence indicates that the listed building has been on the Heritage at [name], there is no compelling evidence before me that the building remains at risk, or that the proposed works are necessary in order to conserve the building. There is also no substantive evidence before me that the proposal is necessary in order to secure the optimum viable use of the asset or that the use of the building as a residential dwelling would cease in the absence of the proposed changes. Consequently, I do not find the proposal necessary to secure the viability or long-term conservation of the listed building.

Overall, I give the public benefits of the appeal scheme limited weight in my decision. Consequently, the public benefits do not outweigh the great weight, which is required to be given to the conservation of heritage assets.

For the reasons given above, I conclude that the proposal would fail to preserve the special interest of the [name] listed building. The proposal would fail to comply with the requirements of the Act and the historic environment policies of the Framework. Conflict also arises with Policies D3 and D4 of the London Plan and Policies 6 and 37 of the Local Plan. These policies among other things require that proposals are of a high standard of design and that the scale, form and materials of a proposal respect or complement those of the host dwelling and that development respects heritage assets.

The appellant has drawn my attention to the decision of [name] v Secretary of State (2021) in which the Inspector held that a 40% volumetric increase could be proportionate, if the new work were clearly subordinate, low in profile and visually contained. However, full details of the circumstances of the other scheme are not before me and I am therefore unable to make any comparison. While the appellant refers to the single storey extension as being low in profile, the appeal scheme also includes a roof extension. In any event every application and appeal must be determined on its own merits, as I have done. Consequently, I give the other scheme limited weight in my decision.

While the Council raises no objections in respect to archaeology, ecology, trees or the living conditions of neighbouring occupants, these are neutral factors and weigh neither for nor against the proposal.

The proposal would be inappropriate development in the Green Belt, which is by definition harmful to the Green Belt. The proposal would also cause harm to the openness of the Green Belt and would fail to preserve the special interest of a [name] listed building. The Framework is clear that substantial weight should be given to any harm to the Green Belt. Overall, I afford the other considerations advanced in this case limited weight in favour of the development. Accordingly, very special circumstances do not exist that clearly outweigh the harm to the Green Belt by reason of inappropriateness and the other harm resulting from the proposal.

For the reasons given above, the proposal would conflict with the development plan as a whole and there are no other material considerations, including the Framework, that would outweigh that conflict. Therefore, I conclude that the appeal should be dismissed. [planning inspector] INSPECTOR