Appeal 3352139

The appeal is dismissed.

An amended version of the National Planning Policy Framework (the Framework) was published on 12 December 2024. In the interest of natural justice and to ensure neither of the main parties were prejudiced, I consulted both parties on the changes to the Framework, and this has informed my determination of the appeal.

The appellant’s statement and plans submitted alongside the appeal appear to contradict each other with regard to the extent of demolition. The Proposed Ground Floor Plan - HD910/6001, [name] (Left) - HD910/6005 and [name] (Right) - HD910/6006 show the demolition of the ramp, annex/outbuilding and pool machinery housing, while in contrast the Proposed Swimming Pool Outbuilding Plan - HD910/6007 and [name] & [name] - HD910/6008 show the demolition of the ramp, boiler housing and pool machinery housing and retention of the annex/outbuilding. The appellant’s statement does, however, clearly outline in red the extent of demolition which would encapsulate the ramp, annex/outbuilding and pool machinery housing. With this in mind, I have dealt with the appeal based on the submitted plans HD910/6001, HD910/6005 and HD910/6006.

Planning permission Ref N08249 was granted in 1986 for the demolition of the original dwelling and the erection of a replacement detached house and garage. In 1987 planning permission Ref N08249A was also granted for a replacement dwelling house. The Council is content that the house depicted in the pre-commencement plans submitted with the appeal is largely based on the house granted planning permission in 1987. It also contends that the appeal property benefits from additional extensions and alterations undertaken through implemented planning permissions. Furthermore, the Council also contend that additional extensions have been undertaken without consent, resulting in [address] becoming extensive in size. I have nothing to establish which parts of the property this relates to and as such I have determined the appeal based on the present circumstances as seen on site.

[address] is located within the Green Belt, alongside a row of large, detached dwellings to the east of [address], with open land used by the [name] to its rear. Levels fall significantly from the front to the rear. The proposed development seeks to demolish the existing single-storey buildings to the rear and retain a part two, part single-storey side and rear extension.

The main issues are: • whether the proposal would comprise inappropriate development in the Green Belt having regard to the development plan and the Framework, and the effect upon the openness of the Green Belt; • the effect of the proposal on the character and appearance of the host property and the surrounding area; and • whether any harm by reason of inappropriateness, and any other harm, would be clearly outweighed by other considerations, so as to amount to the very special circumstances required to justify the proposal.

Policy G2 of the London Plan 2021, Policy CS7 of Barnet’s Local Plan ([name]) Development Plan Document 2012 ([name]) and Policy DM15 of Barnet’s Local Plan (Development Management Policies) Development Plan Document 2012 (DMP) relate to development in the Green Belt. Policy DM15 states, amongst other matters, that development proposals in the Green Belt are required to comply with the Framework. Criterion iv. states that extensions to buildings in the Green Belt or [name] will only be acceptable where they do not result in a disproportionate addition over and above the size of the original building, or an over-intensification of the use of the site.

Paragraph 142 of the Framework specifies that the essential characteristics of Green Belts are their openness and permanence. Paragraph 154 states that development in the Green Belt is inappropriate unless the development falls within the exception list. In this case criterion c) is relevant and states: 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.

The Framework and the development plan provide no specific definition or threshold as to what would amount to disproportionate additions. However, the Council’s Supplementary Planning Document: Residential Design Guidance – October 2016 (the SPD) does set out a guiding principle that extensions to dwellings within Barnet’s Green Belt and [name] should not increase the original volume by more than 25% by external measurement in order to protect openness. It defines ‘original dwelling’ as being that as existed on 1 July 1948, or as originally built if constructed after that date.

Openness has both a visual and spatial dimension and the effect, therefore, not only relates to a proposal’s size or visibility from the surrounding area but also its purpose and intensity of its use. However, openness in any particular case is a matter of planning judgement.

The appellant has undertaken a series of volume calculations to aid the assessment of the planning application and subsequent appeal, and contends that the proposed development would result in an approximately 25.55% greater volume over and above the original house.

Submitted proposed plans detail specific volume calculations relating to the lower ground, ground and first floor, including the roof void. Whilst these volumes have been deducted from the ‘prior to construction’ volume, I have nothing before me that details the specific volume of the swimming pool.

Given this, I am mindful of the appellant’s enforcement appeal [name]/N5090/C/18/3208886. Within this, the Inspector stated that the volume of previous extensions (garage and an enclosed swimming pool) amounted to an approximately 30% increase and that the extensions subject to that appeal increased its volume to approximately 70%.

The swimming pool building is an addition to the original dwelling and would be retained as part of the proposed development. As such, its volume is taken into consideration in the overall calculations.

Whilst existing structures would be demolished and therefore reduce the total volume of [address], there has been a series of extensions which have cumulatively increased its volume. As such, the proposed development cannot reasonably be considered ‘proportionate’ against any metric.

There are clear views from the rear boundary to and from the open land used by the [name]. The existing extensions to the rear currently connect the swimming pool to the main house and extend almost continuously along the shared boundary with its immediate neighbour. Whilst the proposed development would sever this link, it would nevertheless retain the swimming pool and the part two, part single-storey side and rear extension. Taking the development as a whole, including the removal of the existing buildings, I consider that there would still be a noticeable reduction in the openness of the Green Belt which would amount to moderate harm to its openness.

I conclude that the proposal would comprise a disproportionate addition over and above the size of the original building and would therefore be inappropriate development in the Green Belt. It would conflict with [name], CS1 and CS7 of the [name], Policies DM01 and DM15 of the DMP, and Policy G2 of the London Plan. Together these policies seek, amongst other matters, to reflect the provisions of the Framework, which states that inappropriate development should not be approved except in very special circumstances and I return to this matter later in the decision.

Nearby properties on [address] are predominantly large, detached dwellings, consisting of a range of architectural styles. The Council contend that, given the diverse mix in development design within the surrounding area, the proposed development would not result in harm to its character. However, it goes on to state that the cumulative impact of all the building works previously carried out without permission is unacceptable, that they dominate [address] and result in a detrimental impact on its character and appearance and the surrounding area. I have therefore assessed the appeal based on the submitted plans and observations on site.

The demolition of the annex/outbuilding and single-storey buildings would reduce the overall volume of the [address] and create a visual separation between the dwelling and the swimming pool. This would be beneficial to the character of the host property and the surrounding area.

Despite the total depth of the lower ground floor extension projecting approximately 9.17 metres from the rear, and exceeding the overall depth set out in the SPD, the Council has granted previous extensions and alterations which have resulted in the creation of a large dwelling. Whilst the resultant size of [address] may remain large, given that the part two, part single-storey rear extensions are set towards the rear and are not readily visible from the public domain, I am not persuaded that there would be harm to the character and appearance of the host property or surrounding area.

Overall and notwithstanding my findings on the first main issue, I am satisfied that there would be no harm to the character and appearance of the host property and surrounding area. As such, I find no conflict with Policy D3 of the London Plan, Policy CS5 of the [name] or Policy DM01 of the DMP, which collectively seek to ensure that development respects the local context and distinctive local character creating places and buildings of high-quality design. It would also accord with the SPD which seeks, amongst other matters, for rear extensions not to look too bulky and prominent compared to the size of the main building and garden to which they relate.

The Council contends that the proposed development would be contrary to its Local Plan – SPD: [name] and Construction 2016. This guidance, however, sets out the technical requirements for environmental design and construction. As the main issue in this appeal relates to the character and appearance of the host property and the surrounding area, this guidance is not directly relevant.

The appellant has drawn my attention to case law1 with regards to their right to exercise a fallback position. Whilst this is a material consideration, no fallback position has been put forward and I have not been presented with any evidence to suggest the appeal premises has unimplemented planning permission which would constitute as a fallback. As such, any suggestion of a fallback position has limited weight.

Even if the SPD supports the appellant’s suggestion to remove permitted development rights (PD) with regard to outbuildings, the Framework is clear that planning conditions should not be used to restrict PD rights unless there is a clear justification to do so, and that conditions restricting future use of PD rights may not pass the tests of reasonableness. The appellant has only suggested the removal of PD rights with regard to outbuildings. For reasons given above, as I have found harm 1 Mansell v Tonbridge and [name] [2017] [name] 1314 with regard to the part two, part single-storey side and rear extension and the reduction in openness arising from that, I give this suggestion limited weight.

Paragraph 153 of the Framework states that when considering any planning application, local planning authorities should ensure that substantial weight is given to any harm to the Green Belt, including harm to its openness. Inappropriate development is, by definition, harmful to the Green Belt and should not be approved except in very special circumstances. ‘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.

I have found the proposal to be inappropriate development in the Green Belt for the reasons identified. This, together with the harm I have identified to the openness of the Green Belt, amounts to substantial weight against the proposal. The absence of any harm to the character and appearance of the host property and surrounding area is neutral in the overall planning balance. The other considerations which arise have only limited weight in favour of the proposed development and do not outweigh the totality of the harm from inappropriateness and the loss of openness. Consequently, the very special circumstances necessary to justify the development do not exist.

For the reasons set out above, the proposed development would conflict with the development plan and Framework that seeks to protect the Green Belt. There are no other considerations that outweigh this conflict. I therefore conclude that the appeal should be dismissed.