Appeal 6002077

The appeal is dismissed.

The original planning application form contained errors in the appellants’ names; in line with a clarification e-mail sent to the Planning Inspectorate on 10 December 2025 I have used the correct names in the banner heading above.

The main issue is the effect of the proposed development on the character and appearance of the Highgate Conservation Area

The appeal property is within a 19th century group of terrace and semi-detached villas, built in an Italianate style, on the western side of [address]. The site is within the Highgate Conservation Area (“the HCA”), and I have a statutory duty to pay special attention to the desirability of preserving or enhancing the character or appearance of the conservation area. As heritage assets are irreplaceable, the National Planning Policy Framework (“the Framework”) states that they should be conserved in a manner appropriate to their significance (paragraph 202). It goes on to advise that any harm or loss requires clear and convincing justification (paragraph 213) and that any harm that is less than substantial must be weighed against the public benefit of the proposal (paragraph 215).

The HCA covers a close-knit village located on one of the hills of [name]. Its character predominantly stems from its 18th and 19th century architecture, mature greenery, and open spaces. The topography means that long vistas are often possible; along residential streets, across parts of [name], and over urban London to the south. It is from the variety and quality of its townscape, and the verdant spaces and views, that the significance of the HCA is principally derived, insofar as it relates to this appeal.

The Council’s 2007 [name] and [name] document (“the AMP”) notes that the sub-area of the HCA including the appeal property has comparatively dense housing, giving it a more suburban character than much of the rest of the area. The AMP describes the group of eight properties from No 19 to No [address] as “ornate semi-detached villas, with more elaborate stucco decoration1, string courses, overhanging eaves, hipped roofs, ironwork to the windows, coloured tile decoration (some painted white), stucco piers and low front walls”. The entire run from No 15 to No 31 is noted in the AMP as making a positive contribution to the character and appearance of the HCA, though the “prominent roof extensions” at Nos 24, 25 and 26 are among the features listed as detracting from the character of the area.

The proposed development is the creation of a roof terrace, with a dormer on the southern side elevation containing a staircase providing access to the terrace via a hinged rooflight. The Council’s 2021 Home Improvements Camden Planning Guidance Supplementary Planning Document (“the SPD”) sets out a variety of advice in respect of dormers, including that they should sit within the roof slope and appear as an extension to the existing roof while maintaining its existing form, that the glazing element should be emphasised and, for development within conservation areas, that consideration should be given to whether the roof is part of an unbroken roof line of heritage value.

In this case, other than the access rooflight, there would be no windows within the proposed dormer, so it would not comply with the advice in the SPD in respect of emphasising glazing. Although the height of the dormer would sit within the roof slope, it would be relatively broad, and so would add considerable bulk to the side roof pitch of the appeal property. It would also unbalance the symmetry of the appeal property and its semi-detached “twin” at No 22, and so would diminish the positive contribution which the currently unspoiled roofscape of the pair makes to the character and appearance of the area.

I have had regard to other roof terraces and dormers on [address] which were brought to my attention by the appellant, and which I was able to view during my visit. Regardless of whether those developments took place under current development plan policies or, as appears to be the case in respect of a side dormer at No 26, were constructed without planning permission2, they form part of the present context of that part of the HCA. I also however bear in mind (and do not disagree with) the assessment in the AMP that the “large roof extensions and roof terraces at Nos 24, 25 and 26 mar the roofscape”.

[name] have not been provided with the actual measurements, it appears from all the evidence before me that the proposed side dormer at the appeal property would be wider than those at Nos 23 (which does not have a roof terrace), 25 and 26, and similar in width to that at No 24. The proposed terrace would be hidden behind the roof line of No 21, so there would not be the additional clutter and bulk of glazed balustrades or railings, as found at Nos 24, 25 and 26 where the terraces sit on top of the side dormers and flat areas of the main roof. I also acknowledge the appellant’s observation that the proposed dormer at the appeal property would be, and the existing dormers at Nos 23 and 25 are, somewhat less obvious to most people passing on foot along [address] when compared to the 1 That is, compared to the adjacent terrace at Nos 15 to 18. 2 There is no information before me as to when the dormer at No 26 was constructed, including whether it was before the designation or extension of the HCA. dormers and terraces at Nos 24 and 26. This is because the even-numbered properties are on the uphill side of their semi-detached pair and their therefore fall more easily into a natural eyeline than those, like the appeal property, on the downhill side.

Taking these factors together, in view of the size and siting of the proposed dormer at the appeal property I accept that it would be likely to have a lesser visual impact in views along [address] than do the terraces and dormers at Nos 24, 25 and 26. Nevertheless, I still consider that the development would cause significant harm to the character and appearance of the area. This is for two principal

Firstly, although I acknowledge that the group of twelve dwellings from No 15 to No [address] were built in the same period and in the same style, I do not accept the appellant’s characterisation of them as a “distinct and discrete” set of buildings, inasmuch as they do not form a single terrace. While the twelve buildings are physically connected to one another, this is only towards the rear part of the ground and lower ground floors; the narrow but deep gaps give a clear visual separation, and there is no physical connection at first and second floor or roof levels. The four dwellings from No 15 to No [address] of four while, as I have already described above, Nos 19 to 26 are arranged as semi-detached pairs. There are already three roof terraces and four side dormers (25 percent and 33 percent of the twelve respectively), but these are all within the two semi-detached pairs of Nos 23 and 24, and Nos 25 and 26. Within the other two semi-detached pairs Nos 19 and 20, and Nos 21 and 22, and within the terrace Nos 15 to 18, there are no front or side dormers, or roof terraces. The appeal scheme would therefore represent the intrusion of a harmful form of development into buildings within the HCA where it is currently absent.

Secondly, No [address] to the end of [address], which is on the other side of [address] within the adjacent [address] Conservation Area. Although (as I have already set out above) the proposed side dormer would be less visible in views along [address] than other harmful examples nearly, it would be much more prominent in views into the HCA from the east.

The proposed terrace itself, as opposed to the dormer, would be hidden behind the front and rear roof pitches. The front roof slope would be unchanged; the height of the rear roof profile would be reduced slightly, though this would not be so great as to be visually discordant. I note the Council’s concern that the creation of the terrace “would require substantial alteration and removal of existing roof fabric”, but there is nothing before me to indicate that the building fabric itself is of historical or heritage significance. Other than insomuch as its balustrades would connect to, and would therefore be perceived as part of, the side dormer, I do not consider that any significant harm to the character or appearance of the HCA would arise from the creation of the terrace itself. However, this does not outweigh the other harm I have found.

The Council’s officer report referred to the Grade II Listed “[address]” 3, on [address] at the rear of the appeal property. It was suggested that the appeal proposal would be “likely to have a negative impact” on the setting of that building, though this was not referred to in the decision notice, nor was the matter 3 [name] 1322115 elaborated upon in the Council’s appeal statement. I was able to view the [address], and the relationship between it and the appeal property, during my site visit. The setting of the [address], insofar as it relates to this proposal, is defined by the narrow lane of [address], which has dense and mature evergreen vegetation along its eastern side boundary with the rear of properties on [address]. Because of the physical and visual separation between the appeal scheme and the [address], I am satisfied that the setting of the Listed Building would be preserved. Again though, this does not alter my overall conclusion on this main issue.

The appellant drew my attention to a 2024 allowed appeal relating to a scheme described as a “fourth floor rear roof extension and erection of fifth floor roof extension to form one bedroom”, at [address] within the Royal Borough of Kensington and Chelsea4. While there are of course differences in the local development plan policies and guidance, I acknowledge that there are common issues between the two appeals – including the consideration of changes within a conservation area, and the extent of such changes – which are relevant material considerations here.

I have not been provided with the full details of that scheme, but note that my colleague in Kensington and Chelsea was dealing with what they clearly considered to be a single terrace of 12 residential properties. Accordingly, they evidently gave the extent of changes which had already been made to the block (notably that a quarter of it had been extended upwards by the addition of a storey) significant weight in their assessment. Here, for the reasons I have set out in paragraph 12 above, I consider that the appeal property should not be treated as being part of one significantly-altered block. I also note that the type of development before me has been specifically identified in the AMP as being harmful to the HCA, while there is nothing in the [address] decision to indicate that was the case there. Overall, I consider that the circumstances of the two sites are sufficiently different that my reaching a different conclusion is justified.

For the reasons I have set out above, I conclude that the proposed development would be harmful to the character and appearance of the HCA. It would therefore conflict with Policies D1 and D2 of the 2017 Camden Local Plan, and with Policies DH2 and DH5 of the 2017 Highgate Neighbourhood Plan. Together, and among other things, these polices seek to ensure that new development respects local character, preserves or enhances the historic environment and heritage assets including conservation areas, and that roof extensions and dormers within the HCA should be restricted to the rear except where they are part of the established local character.

In the Framework’s terms, the harm to the significance of the HCA as a designated heritage asset would be less than substantial and, indeed, given the large size of the HCA and the small scale of the scheme, towards the lower end of that categorisation. I acknowledge that there would be private benefits to the appellants from being able to enlarge their home with a private roof terrace, but no public benefits have been identified which would outweigh the harm I have identified. The proposal would therefore also conflict with the provisions of the Framework which seek to preserve and enhance the historic environment. 4 [name]: APP/K5600/W/23/3329256

The appellant brought several examples of caselaw to my attention during the appeal: the Palmer5 and South Lakeland6 judgments relating to the assessment of development impacts on conservation areas and Listed Buildings, and the North Wiltshire7 judgment which dealt with consistency in decision making. I am satisfied that that my decision in this appeal is in accordance with these relevant precedents.

The proposed development would be harmful to the character and appearance of the HCA. This harm, which must be afforded great weight, would not be outweighed by any public benefits of the scheme. The proposal would conflict with the development plan taken as a whole. There are no material considerations that indicate the decision should be made other than in accordance with the

The appeal is therefore dismissed.