Appeal 3343608

The appeal is dismissed.

During the course of the appeal a revised National Planning Policy Framework (the Framework) was published in December 2024. However, as any policies in the Framework that are material to this decision have not fundamentally changed, I am satisfied that neither party would be prejudiced by my consideration of the revised Framework in reaching my decision.

The main issues are: • Whether the proposal would be inappropriate development in the Green Belt having regard to the Framework and any relevant development plan policies, and the effect on the openness of the Green Belt and purposes of including land within it, and • If it is inappropriate development, whether the harm by reason of inappropriateness, and any other harm, is clearly outweighed by other considerations so as to amount to the very special circumstances necessary to justify it.

The appeal site comprises a detached two storey dwelling in a modest sized garden at the end of a private drive, overlooking the playing fields of the recreation ground. According to the planning history the property has been extended over time with a first floor side extension and single storey and two storey front extensions. A Lawful Development Certificate (LDC) has also been granted1 for a two storey rear extension 1 LPA ref: CB/23/03475/LDCP granted 20 December 2023 and a single storey side extension to be built under permitted development2. This has not been built, as was evident from my site visit

Framework paragraph 142 states that the Government attaches great importance to Green Belts. Paragraph 153 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. Paragraph 154 states that development in the Green Belt is inappropriate unless one of the listed exceptions applies. As the proposed development would be an extension to a building, it falls to be considered under exception 154c) regarding the extension or alteration of a building provided that it does not result in a disproportionate addition over and above the size of the original dwelling. The term ‘original dwelling’ is defined in the Framework Glossary as the building as it existed on 1 July 1948, or if constructed afterwards, as it was built originally.

Green Belt Policy SP4 of the Central Bedfordshire Local Plan (2015-2035) sets out that development proposals will be assessed in accordance with government guidance in the Framework and Planning Practice Guidance. It reflects the general thrust of the Framework.

Neither the Framework nor Local Plan define ‘disproportionate’. However, the Framework refers to size, which requires consideration of external dimensions, floor area, footprint and volume. It can also involve consideration of matters such as scale, bulk and massing. The Council’s Design Guide3 provides further advice for assessing whether extensions to dwellings in the Green Belt are ‘proportionate’. The guiding principle is that the original building should not be added to by more than 60% of its footprint, floorspace and volume. The impact in terms of massing and design will also be considered.

The Council sets out the calculations in its delegated officer report, which the appellant does not dispute. Taking account of previous extensions that have been built, the proposed two storey extension would result in a cumulative increase in the footprint of the dwelling by about 36% and about a 73% increase in the overall floor area. Whilst the floor area increase would exceed the 60% proportionate guidance, and be contrary to the Council’s Design Guide, the resulting footprint would be within the guidance level.

In addition to extending the linear dimensions for footprint and floor area the extension would also increase the volume of the property, although no calculations have been provided. In terms of design and massing, the front elevation would be enlarged by the two storey extension. Although the ridge line of the extension would sit lower than the main roof ridge of the house, there would be a longer extent of roof linking the extension roof to the main house. The flank side elevation would have a twin gable, somewhat at odds with the orientation of the main dual pitched roof, that would increase the apparent bulk and massing of the extension.

Taking account of all these components and previous extensions, the proposed extension would be a disproportionate addition over and above the size of the original building. Accordingly, the proposal would be inappropriate development as described in 2 Under the Town and Country Planning (General Permitted Development) (England) Order 2015 (as amended) 3 [name] - August 2023 exception paragraph 154c) of the Framework and would be contrary to Local Plan Policy SP4. It would also conflict with the Council’s Design Guide.

The Framework states that the fundamental aim of national Green Belt policy is to prevent urban sprawl by keeping land permanently open and that the essential characteristics of Green Belts are their openness and their permanence. There is no definition of openness in the Framework or the development plan, but the courts have established that openness has both a spatial and a visual aspect and a number of factors are capable of being relevant to openness, depending on the particular facts of a specific case. Hence the effect on openness is a matter of planning judgement.

The appeal site is garden. The property is adjacent to fields and the playing fields of the recreation ground. Hence, the openness of the Green Belt is clearly evident. The proposal would involve introducing built form where none currently exists and the proposal would have a footprint that would occupy open space on the ground. Furthermore, the proposed extension would be a substantial two-storey, three dimensional structure that would have floor area, height, mass, bulk and volume. Consequently, the proposed extension would materially reduce the spatial and visual openness, and thus would have a harmful effect on the Green Belt in this location.

The appellant advances that the permitted development extensions approved under the LDC are bigger than the proposed extension and hence this is a ‘fallback’ position, which is a material consideration that justifies allowing the appeal scheme. An LDC is not a planning application, so that the planning merits of the case and Green Belt issues did not fall to be considered.

I have had regard to Mansell v Tonbridge and West Malling Borough Council4. I have no reason to doubt that there is a theoretical possibility that the LDC extensions could be built. Therefore the fallback position is relevant and capable of being a material consideration.

However, for significant weight to be afforded to a fallback position there needs to be not only a reasonable prospect of it being carried out in the event that planning permission was refused, but the fallback would also need to be equally or more harmful than the scheme for which planning permission is sought.

Both schemes would offer similar accommodation as both would provide enlarged living space on the ground floor and extra bedroom space upstairs and both schemes would involve associated internal reconfiguration. Numerically, the proposed extension would have a smaller footprint and smaller floor area than the LDC extensions, although the floor area of the appeal proposal would still exceed the Council’s 60% ‘proportionate’ guideline.

However, the configuration of the two schemes differs. The LDC scheme comprises two separate extensions on different elevations of the building which are not linked internally or externally. This would physically and visually break up their bulk and massing. Due to the dwelling’s open aspect and elevated position, the front and side 4 Mansell v Tonbridge and West Malling Borough Council [2017] [name] 1314 elevations of the dwelling are highly visible from the nearby [name] car park and when travelling west through the village. The LDC scheme would have a single storey side extension that would have limited visual impact on openness, and a simpler roof form that would reduce bulk and massing. In contrast, the design and form of the proposed twin gable two storey extension would have greater physical and visual presence.

I therefore find the proposed extension would have a greater overall impact on openness than the LDC scheme that could be built as permitted development. In other words, the fallback scheme would be less harmful than the scheme for which planning permission is being sought and therefore cannot carry significant weight. Imposing a condition to remove permitted development rights to prevent the rear extension of the fallback scheme being built would not overcome my concerns about the appeal scheme.

The appellant draws my attention to an appeal in Dukes Valley5 whereby the Inspector gave a fallback position for an extension significant weight. That was because they found the fallback scheme would be more harmful compared to the appeal scheme. That is not the case for this appeal. Even if comparisons can be made between the extensions, all appeal decisions turn on their own particular circumstances based on the facts and evidence before those Inspectors at the time. In any event, I must consider the appeal on its own merits.

The development represents inappropriate development in the Green Belt, which is, by definition, harmful to the Green Belt. Under Framework paragraph 153 substantial weight is to be given to any harm. There would also be a loss of openness. Harmful inappropriate development in the Green Belt should not be approved except in very special circumstances. Very special circumstances to justify inappropriate development will not exist unless the potential harm to the Green Belt, by reason of inappropriateness and any other harm, is clearly outweighed by other considerations.

I give limited weight to the fallback position for the permitted development extensions under the LDC application and to the short-term economic benefits during the construction phase in terms of jobs and expenditure. However, taken alone or together, they do not clearly outweigh the totality of harm, which is the test that they have to meet, in light of the national importance given to protecting the Green Belt relative to the modest private benefits that would accrue from the appeal development. Consequently, very special circumstances to justify the proposed development do not exist.

The proposal would conflict with the development plan as a whole and there are no other considerations that outweigh this finding. For all the above reasons, I conclude that the appeal should be dismissed.