Appeal 3353146

The appeal is dismissed.

Since the application was determined, a revised National Planning Policy Framework (NPPF) was published in December 2024. However, although changes have been made to Green Belt policy, those policies that are material to this decision have not changed. I am therefore satisfied that this has not prejudiced any party. I have had regard to the latest version of the NPPF and new paragraph numbers in reaching my decision.

The main issues are: firstly, whether the proposed development would amount to inappropriate development in the Green Belt, having regard to the NPPF, 2024, and any relevant development plan policies; secondly, the effect on the openness of the Green Belt and on its character; thirdly, whether the proposed annex would be capable of separation from the existing dwelling; and fourthly, if the proposed development would amount to inappropriate development, whether the harm by reason of inappropriateness and any other harm is clearly outweighed by other considerations, such as to amount to the very special circumstances necessary to justify the development.

The appeal site comprises a large, detached house on an extensive plot facing the busy A10. It lies at the end of a row of dwellings in a semi-rural area in the Green Belt. The evidence indicates that planning permission was granted for an extension to the dwelling in 1981 but I have no information regarding its size or whether it was implemented. There is a large, single storey building to the south of the dwelling which houses a swimming pool. This building appears to be of modern construction but I have no evidence as to its origin including when it was built. The Council assesses the existing footprint of the dwelling to be approximately 164.5m2.

The proposed annex would be sited in the south-west corner of the appeal site, adjacent to the boundaries of dwellings in [address] and a considerable distance from the host dwelling. The Council states that it would have a footprint of about 99m2. The appellant does not dispute the Council’s figures.

The Council’s refusal notice states that the proposed annex would conflict with [name]/4 and H/13 of the South Cambridgeshire Local Plan (LP), 2018, which state that new development in the Green Belt will only be approved in accordance with Green Belt policy in the NPPF and that an extension should not result in a disproportionate addition to the original dwelling.

The NPPF identifies that the fundamental aim of Green Belt policy is to prevent urban sprawl by keeping land permanently open. It goes on to state that inappropriate development is, by definition, harmful to the Green Belt and should not be approved except in very special circumstances. New buildings are considered inappropriate unless they fall within certain exceptions. For extensions and alterations to buildings, these should not result in disproportionate additions over and above the size of the original building. “Original building” is defined in the NPPF as a building as it existed on 1 July 1948 or, if constructed after 1 July 1948, as originally built. LP Policy H/13 accords with this. The courts have held that an “extension” does not have to be attached to the host building to be considered as such for Green Belt purposes.

The Council has assessed the proposed annex as an extension to the host dwelling and calculates that its footprint would be in excess of 50% of that of the host dwelling. This, it is considered, would amount to a disproportionate addition over and above the size of the original building. In view of the limited information regarding previous extensions or the status of the swimming pool building, I consider that the identified increase would represent the best case scenario since enlargements are assessed cumulatively and it appears likely that additions since 1 July 1948 have already enlarged the original building. Therefore, the actual cumulative increase may be greater but would not be less. On this basis, I agree with the Council’s assessment.

It is concluded on the first main issue that the proposed development would amount to inappropriate development in the Green Belt. The NPPF advises that substantial weight should be given to any harm to the Green Belt, including that by reason of inappropriateness.

The NPPF states that the essential characteristics of Green Belts are their openness and permanence. Openness has a spatial and visual aspect. The appeal annex would not be visually prominent from the open countryside, although it would be visible from dwellings and their gardens in [address]. Its effect on visual openness would thus be limited. Nevertheless, its scale would have a noticeable effect on the spatial openness of the site, notwithstanding that it would replace a smaller greenhouse. Overall, the effect on openness would therefore be moderate.

With respect to the effect on the character of the Green Belt, the proposed annex would be sited a considerable distance from existing built development at the appeal site and would be separated from dwellings in [address] by their large gardens. It would be sited in a mostly undeveloped part of the appeal site that is characterised by its semi-rural appearance and by nearby shrubs and trees. I therefore agree with the Council that it would have a noticeably adverse effect on the rural character of this part of the site.

It is concluded on the second main issue that the proposed development would, result in moderate harm to the openness and character of the Green Belt. This would conflict with LP Policy NH/8 which expects proposals within the Green Belt to be located so that they do not have an adverse effect on the rural character and openness of the Green Belt. Since substantial weight should be given to any harm to the Green Belt, including loss of openness and harm to its character, the identified harm weighs heavily against the proposed development.

LP Policy H/13 resists extensions to dwellings in the countryside that are outside village framework boundaries and that would create a separate dwelling or would be capable of separation from the existing dwelling. The Council considers that as the proposed annex would provide all of the accommodation necessary to form a separate dwelling, since there would be potential for an access and parking that could be separate from the main dwelling and due to its siting, remote from the host dwelling, it would conflict with this policy.

The appellant points out that the building applied for is an annex that would be used in conjunction with the host dwelling and that this could be controlled by a suitable planning condition so that any change of use to an independent dwelling would require planning permission. I agree. I therefore conclude on the third main issue that, subject to a restrictive condition, the proposed annex would not be or be capable of lawfully becoming a separate dwelling, other than through an express grant of planning permission. This matter weighs neither in favour of nor against the proposed annex and is neutral in terms of the Green Belt.

The appellant draws my attention to the fact that the proposed annex is required to provide accommodation to extended family members, including potentially, the elderly. However, I have no specific details of need. Moreover, this is not an unusual circumstance. I therefore afford it limited weight in favour of the proposed development.

Although not advanced by the appellant, I also consider that the construction of the proposed building would have some economic benefit in terms of its construction, maintenance and use. However, this benefit would not be great, and I afford it limited weight.

Accordingly, it is concluded on the fourth main issue that, in the final balance, the other considerations would not clearly outweigh the harm to the Green Belt through inappropriateness, loss of openness and harm to its character. Consequently, the very special circumstances necessary to justify the development do not exist. The proposed development would therefore conflict with [name]/4, H/13 and NH/8, and with national policy set out in paragraphs 142, 143, 153 and 154 of the NPPF, 2024.

For the reasons set out above and having regard to all other matters raised, including the representations of third parties regarding amongst other things, outlook, flooding and loss of trees, I conclude that the appeal should be dismissed.