Appeal 6003016

The appeal is dismissed.

Article 3(1) and Schedule 2, Part 20, Class AA of the Town and Country Planning (General Permitted Development) (England) Order 2015 as amended (GPDO 2015), permits the construction of up to two additional storeys of new dwellinghouses immediately above the topmost storey on a detached building.

Development is permitted under Class AA subject to the limitations set out under [name].1. and the conditions set out under [name].2, which include matters in respect of which the developer must apply to the local planning authority for prior approval.

The Council found that the proposal would comply with the conditions and limitations set out at paragraph AA.1 of Class AA, such that it would fall within the scope of permitted development rights, subject to the consideration of relevant matters of prior approval. On the evidence before me I see no reason to take a different view.

The Council has, however, raised concerns in respect of the effect of the development upon the external appearance of the host property and locality. The condition under paragraph AA.2 (1)(e)(i) is that before development the developer must apply to the local planning authority for prior approval as to the external appearance of the building, including the design and architectural features of (aa) the principal elevation, and (bb) any side elevation that fronts a highway.

The Council has referred to various policies in the Hillingdon Local Plan within the [name]. I have taken account of the content of those policies insofar as they may be relevant to the context of the specific prior approval matters. However, the policies are not determinative and I have considered the proposal on its merits in the confines of the prior approval regime.

In making my assessment of the merits of the proposal I have taken into account the judgement made in the High Court1 regarding the interpretation of Class AA of Part 1 of the GPDO. This judgement, although specifically relating to development under Part 1 Class AA, indicates that a wider interpretation of external appearance could be used in the assessment of [name] applications under Part 20. In particular it indicates that control of the external appearance is not limited to the impact on the subject property itself, but also includes impacts on neighbouring premises and the locality.

The main issue is whether prior approval should be granted having regard to the requirements of Part 20, Class A paragraphs AA.2 (1)(e) relating to the effect of the proposal on the external appearance of the building.

The appeal property is situated close to the roundabout junction of [address], [address], [address] and [address]. Building heights in the wider vicinity vary, ranging from two-storey dwellings to three and four storey mixed use buildings. Directly opposite the appeal site are three storey residential flats and located either side of the principal elevation of the host property are three storey buildings.

The principal elevation of [site address] (No 117) has commercial units on the ground floor with residential accommodation above. It is four storeys in height with the fourth floor stepped back from the third. The principal elevation is set slightly back from the established building line of the adjacent three storey property to the east. Its modern design contrasts with the traditional brick built properties making it a prominent feature within the street scene. However, because its roofline forms a gradual stepped transition with the lower three and two storey properties to the west, and its height is only marginally greater than the adjacent prominent three storey building located on the corner of [address] and [address] against which it is primarily viewed, the building does not appear harmfully dominant in the locality, nor does it disrupt the relative uniformity and rhythm of the building heights on this part of [address].

The proposed additional storey would use materials that match the fourth floor of the building and would be recessed from the current top floor, thus continuing the stepped appearance of the principal elevation. In this regard, it would not appear top heavy or unbalance the composition of the building itself.

However, notwithstanding the above, the increased scale would be highly conspicuous within the street scene. The additional height would make No 117 appear considerably taller than the other buildings in the immediate vicinity, harmfully contrasting with the roof heights of the neighbouring buildings. The proposal would therefore appear as an unduly prominent and incongruous addition and would fail to sit comfortably against the heights of the adjacent buildings. That 1 CAB Housing Ltd, Beis Noeh Ltd & [name] v SSLUHC [2022] EWHC 208 (Admin) the principal elevation of the appeal building is set back from the neighbouring buildings would not mitigate its prominence or harmful visual effect.

[name] note the presence of other tall buildings close to the appeal property, such as [name] and [name], these are located on the opposite side of the road and roundabout. They are read in a different spatial context to the appeal building within a more spacious setting. In contrast, the appeal property, is primarily viewed in the context of its adjacent properties, the continuous frontage of the three storey property on the corner of [address] and [address] and the three storey residential building immediately to the west. The presence of the taller buildings nearby does not alter my findings and does not justify the introduction of such a conspicuous addition to the appeal building.

I acknowledge that large scale buildings previously occupied the site, however I have limited information as to how these buildings assimilated within the street scene. In any case, my determination is based on the current context and how the external appearance of the proposal would assimilate within it. In reaching this view, I have taken into account the large scale of the existing building and the presence of other tall buildings in the wider locality.

In conclusion, I find the proposal would not be acceptable in terms of its external appearance, having an adverse effect on the locality by reason of its design through the increased height and scale. Accordingly, it would not comply with paragraph AA.2 (1)(e) of Schedule 2, Part 20, Class AA of the GPDO.

For the above reasons, I conclude that the proposal would not comply with paragraph AA.2 (1)(e) of Schedule 2, Part 20, Class AA of the GPDO and prior approval should therefore not be granted. The appeal is dismissed.