Appeal 6002321

The appeal is dismissed.

The site address in the above banner heading is taken from the decision notice rather than the application form. This is because it is replicated in the appellant’s appeal statement, and I have no reason to dispute its accuracy.

Schedule 2, Part 20, Class AA of the Town and Country Planning (General Permitted Development) (England) Order 2015 (the GPDO) permits development consisting of works for the construction of up to two additional storeys of new dwellinghouses immediately above the topmost storey on a detached building used for certain listed purposes, including Class A2 (financial and professional services). The main parties do not dispute the lawfulness of this use of the appeal site, and I have no reason to disagree.

The condition set out in paragraph AA.2 (1) requires the developer to apply to the local planning authority (LPA) for prior approval as to several specified issues before beginning development. This includes the external appearance of the dwellinghouse. This appeal follows the LPA’s decision to refuse prior approval, as it determined that the proposal would be harmful in respect of that issue.

The Council’s reason for refusal also states that the proposal would “constitute inappropriate overdevelopment of the site, undermining the established local pattern of development and urban grain, and detracting from the visual amenity of the streetscene and the character and appearance of the area”. Case law1 has held that where prior approval is required in relation to the effect on the external appearance of a dwellinghouse, the decision maker can consider this effect both in 1 CAB Housing Ltd v SSLUHC & [name] [2023] [name] 194. terms of on the building itself, and on its surrounding area. I have therefore determined the appeal on this basis.

Although not forming a reason for refusal, the LPA has expressed uncertainty as to whether the appeal building is detached. This brings in to dispute whether the appeal building benefits from the provisions of Class AA as set out above.

There are therefore two main issues: • whether the proposed development benefits from the provisions of Class AA of the GPDO; and if the proposal is found to constitute permitted development • whether prior approval should be granted as to the external appearance of the appeal building, including the surrounding area.

For the purposes of Part 20, the GPDO states that the term “detached building” means a building which does not share a party wall with a neighbouring building. In the absence within the GPDO and the Town and Country Planning Act 1990 of a definition of what constitutes a party wall, I am directed to the [name] etc Act 1996 (the 1996 Act) and the Government’s Party Wall etc Act 1996 explanatory booklet (published 12 May 2016). My attention is also drawn to an appeal decision at another site2 where this same matter was in dispute.

The 1996 Act states that “party wall” means, amongst other things, a wall which forms part of a building and stands on lands of different owners to a greater extent than the projection of any artificially formed support on which the wall rests. No ownership details are before me, and neither is there technical evidence such as a building survey or structural report. However, during my site visit, I observed a very small gap at the rear of [address] between the appeal building and the adjacent building of No 227, which appears to have its own separate side wall.

I have no reason to dispute the accuracy of the submitted floor plans of the appeal building, which indicate a side wall of substantial thickness within the appeal site, alongside and abutting No 227. This does not appear to form a type of single shared wall between the two buildings that would be subject to the 1996 Act’s definition of a party wall. For the above reasons and based on the evidence before me, I have found that the appeal building is detached for the purposes of Class AA, and thus benefits from this permitted development right.

There is no dispute between the main parties in respect of the other Class AA provisions. I therefore conclude that the proposal constitutes permitted development. It follows that I must also consider the disputed prior approval matter of the external appearance of the appeal building, including the surrounding area.

The appeal building is within a corner site at the junction of [address] and [address]. It contains three storeys and I noted some taller buildings on higher ground facing [address]. Nearby buildings along [address] are however lower, being predominantly up to three storeys in height, including No 221- 2 Appeal Ref: APP/M5450/W/21/3289938 ([address], London)

Whilst there is some variation in the rooflines, including scale, with some more ornate roofscapes of some historic interest, there is a strong uniformity shared by many of the [address] buildings.

I accept that the upwards extension would follow the design cues of the appeal building in terms of the fenestration proportions and rhythm, and matching brickwork, render and glazing materials are proposed. This design approach seeks to create a natural vertical continuation of the existing building, rather than a visually separate structure.

Addition of two storeys as proposed would however lead to an abrupt and significantly higher roofline than that of No 221-227. Whilst there are some taller buildings facing [address] in the wider vicinity, their topmost floors are noticeably recessed back from the [address] frontage to avoid over-dominant visual impacts.

The proposed two storey upward extension would therefore not sit comfortably within this [address] context, as it would harmfully disrupt the gentle rhythm of the [address] rooflines. It would appear visually jarring when compared to the more incremental and discreet height variation that is characteristic of the appeal site’s [address] context. The additional height and bulk would go beyond a natural, logical or visually coherent bookend role often found in corner plot locations.

Provision of recessed external terrace spaces would not break up the proposed bulk or massing to a meaningful degree. The street or block edge location, and the visual differences with No 221-227, would also not mitigate the harmful visual impact that I have identified.

A proposed increase in building height does not automatically equate to visual harm, and such an approach would frustrate the purpose of the grant of permitted development rights through Class AA. Namely, to incentivise and speed up housing. However, for the above reasons, I have found that the appeal proposal would appear visually harmful when having regard to its context.

My attention is drawn to a [name] granted by the LPA in recent years for a two-storey upward extension on the neighbouring site of No [address]. Although this did not appear to have been implemented at the time of my visit, the appellant contends that it remains extant, which the LPA has not disputed. Like cases should be considered in a like manner. However, based on the evidence before me, this neighbouring scheme is notably set back from the existing elevation facing [address], and is also notably set away from the appeal site.

By contrast, the appeal proposal materially differs in terms of its integrated form with the appeal building elevations, and its corner plot location, which would result in a notably more dominant development. Therefore, whilst the abovementioned neighbouring scheme forms a relevant material consideration, its appearance and context materially differ from the appeal proposal such that it does not justify allowing this appeal.

The proposal would not comply with Policies 4 and 37 of the Council’s Local Plan (adopted 2019) and Policy D3 of the London Plan, insofar as they are relevant to this prior approval matter. Such policies are however not in themselves determinative, as by introducing Class AA permitted development rights, the Government clearly envisaged that there would be a degree of change to certain properties. That being said, such rights are qualified by the need to apply for prior approval, as set out above, even if this involves a lighter touch approach or lower design quality bar than proposals requiring full planning permission.

For the above reasons, I conclude that prior approval should not be granted, due to the harmful effect that the proposal would have on the external appearance of the appeal building, including the impact on the surrounding area.

The reason for refusal also cites conflict with Policy D4 of the London Plan. This policy refers to, amongst other things, masterplans, design codes and design and access statements. However, as these are not prior approval requirements, this policy is not relevant to the appeal proposal.

I have considered development plan policies only insofar as they are relevant to the prior approval matter, and in the context of the GPDO’s purpose of increasing the supply of housing. However, prior approval appeals cannot be determined having regard to s38(6) of the Planning and Compulsory Purchase Act 2004, or as though the development plan must be applied. This is because the principle of development is established through the grant of permission by the GPDO.

Moreover, whilst Part 20 prior approval matters require regard to be had to the National Planning Policy Framework (the Framework), such regard applies only where the Framework is relevant to the subject matter of the prior approval3. Therefore, matters relating to the LPA’s housing land supply, the Framework’s presumption in favour of sustainable development, and its economic, social and environmental objectives, are not relevant considerations that can be afforded any positive weight to allow the appeal.

The LPA cites conflict with the Orpington Town Centre Supplementary Planning Document (adopted 2023). However, as the design advice within this adopted guidance does not account for the provisions of the Order, it has had no bearing on my determination of this appeal.

For the reasons given, the appeal is dismissed.