For a front gable feature, alterations to fenestration to include relocated front door, single storey front/side extension, single storey rear/side extension, part raised ridge, 2no

Appeal Decision Site visit made on 21 July 2026 by S Ramsden BSc (Hons) MA MA IHBC an Inspector appointed by the Secretary of State Decision date: 04 September 2026 Appeal Ref: 6009260 2 Island Cottages Stanwell Road, Horton, Windsor, Slough SL3 9PQ • The appeal is made under section 78 of the Town and Country Planning Act 1990 (as amended) against a refusal to grant planning permission. • The appeal is made by Mr Gurdeve Singh against the decision of Royal Borough of Windsor and Maidenhead. • The application reference is 25/03424/FULL. • The development proposed is for a front gable feature, alterations to fenestration to include relocated front door, single storey front/side extension, single storey rear/side extension, part raised ridge, 2no. front, 2no. side and 2 no. rear dormers with Juliet balcony, following demolitio n of existing elements. Decision 1. The appeal is dismissed. Preliminary Matters 2. A revised version of the National Planning Policy Framework (the Framework) was published on 17 August 2026. The changes to the Framework do not affect the merits of this case in a material way and I, therefore, have not consulted the parties with regard to these changes. Main Issues 3. The main issues are: • whether the proposal is inappropriate development in the Green Belt having regard to the Framework and relevant development plan policies; • the effect on openness of the Green Belt; • the effect of the proposed extension upon the character and appearance of the host property and the surrounding area; • whether the identified flood risk has been sufficiently assessed and would be appropriately mitigated against and; • whether the 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. Reasons 4. The appeal site comprises a semi-detached bungalow, situated on a small, narrow island formed by two branches of the Colne Brook, accessed by a short track off Stanwell Road. The house dates from the 1960s, but appears heavily altered having been extended subsequently on a number of occasions. The attached bungalow has also been extended, including with dormer windows to its roof. Appeal Decision 6009260 2 5. Other than the two houses, which have numerous outbuildings, the island contains a large electricity pylon in an area of rough pasture immediately to the rear of the appeal site. Although the surrounding land is flat, the island appears relatively enclosed by trees and vegetation. The surrounding area comprises a mixture of small villages and pockets of residential development, interspersed with gravel pits, small fields, reservoirs and semi-industrial/commercial units. The character of the area is also influenced by its proximity to the flightpath of aeroplanes from Heathrow Airport, which lies to the east. The appeal site is in the Metropolitan Green Belt. 6. The proposed development would occupy a similar footprint to the existing building, although it is proposed to replace the existing roofs of No 2 with a raised, predominantly flat-roof structure. The roof would have pitched elements to each side, some with dormers containing glazed doors with Juliet balconies. Although there are no stairs shown on the ground floor plan, this appears to be intended as an additional floor level within the roof space. This view is reinforced by reference to a first floor level in the appellant’s statement of case. Whether inappropriate development 7. The five purposes of Green Belts are listed in policy GB2.1 of the Framework. The Framework states that ‘inappropriate development’ is, by definition, harmful to the Green Belt and should not be approved except in very special circumstances. Development in the Green Belt is inappropriate unless one of the exceptions listed in policy GB7 applies. 8. One exception given in policy GB7.1.b of the Framework is 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. 9. The proposed development would result in a dwelling which would, by floor area, be around 170% of the original 1960s bungalow. This would increase to around 270% if a first floor is included in the calculations. Both figures indicate a disproportionate addition over and above the size of the original building. The proposed development would also entail a significant increase in the volume of the building. 10. For these reasons, I conclude that the proposal would be inappropriate development in the Green Belt under policy GB7.1.b of the Framework. Openness 11. The Framework states that the Government attaches great importance to Green Belts, the fundamental aim of which is to prevent urban sprawl by keeping land permanently open. 12. The Framework describes that the essential characteristics of Green Belts are their openness and their permanence. There is no definition of openness in the Framework, but the courts have established that openness has both a spatial and a visual aspect. Assessment of openness is a matter of planning judgement based on the specific facts of the case. 13. The increase in size and volume of No 2, would result in harm both spatially and visually to the openness of the Green Belt. However, any impacts would be localised and limited, given the location of the appeal site, the extent of visual Appeal Decision 6009260 3 enclosure, the nature of its surroundings and nearby development. Whilst harm to the Green Belt would be limited in nature, as set out in the Framework, it nevertheless attracts substantial weight. Character and appearance 14. The proposal is described as alterations and extensions to the existing bungalow although, given the extent of the extensions and the proposed new roof structure, little of the existing dwelling would remain discernible. 15. Whilst the proposed development would, to some extent, unify the various accretions that have been added to No 2, the proposed roof form would be unconvincing, either as a flat roof extension or as a traditional hipped roof. Its form would relate poorly to either the host building, that of its immediate semi-detached neighbour, or more traditional roof forms in the wider area. The number and size of the proposed dormers would draw further attention to the disproportionate bulk, in comparison to the ground floor, of the roof. 16. Similarly the two-storey, glazed central entrance feature would contrast unfavourably with the solidity of the host building. The misalignment of the various dormers with the ground floor windows, along with the varying roof pitches, would not add to the visual coherence of the overall design. 17. For these reasons, the proposed development would not constitute high quality design, and would relate poorly to its surrounding context. Although there would be limited visibility of the development from the public domain, that does not diminish the harm I have found on this issue. 18. The proposed development would therefore conflict with Policy QP3 of the Royal Borough of Windsor & Maidenhead Borough Local Plan (the Local Plan) 2022, which seeks to deliver high quality design that enhances its local context. It would also conflict with Policies NP/HOU1 & NP/HOU2 of the Horton and Wraysbury Neighbourhood Plan (the Neighbourhood Plan) 2020, which taken together seek to deliver good quality design which makes a positive contribution to the character and sense of place of the built environment and landscape. 19. The proposed development would also not comply with Principles 7.7 and 10.5 of the Borough Wide Design Guide (2020), which seek to resist the introduction of roof forms on development that diverge from the prevailing character and ensure roof alterations are sympathetic and subservient to the design of the main building. Flood Risk 20. The appellant states that the appeal site is in Flood Zone 2, whereas the Council submit that it is in Flood Zone 3. However, standing advice from the Environment Agency (the EA) for minor household extensions is the same in both instances. 21. The appellant has submitted a flood risk assessment (FRA); however it is incomplete as certain sections are blank. It does not address river flooding with a 1 in 100 annual probability plus an allowance for climate change, as is required by current EA standing advice. 22. The proposed development has approximately the same footprint as the existing building and would contain a similar range of rooms at ground floor. The proposed development would also have a similar floor level to the existing building, and as Appeal Decision 6009260 4 such there is unlikely to be a significantly different flood risk associated with the proposed development than currently exists.  23. The FRA proposes a range of flood proofing and resilience measures. It would be possible to secure such measures by planning condition, along with any additional requirements from a 1 in 100 annual flood probability when known, were I not dismissing the appeal for other reasons. 24. However, based on the information submitted the identified flood risk has not been sufficiently assessed nor would it be appropriately mitigated against. Accordingly the proposed development conflicts with Policy NR1 of the Local Plan which requires that an appropriate flood risk assessment has been carried out and it has been demonstrated that development is designed to ensure that flood risk from all sources of flooding is acceptable. 25. Similarly the proposed development does not accord with Policy NP/SUSTDEV 02 of the Neighbourhood Plan, which seeks to encourage development that is as flood resilient as possible. Green Belt balance and Conclusion 26. The proposal constitutes inappropriate development in the Green Belt which is, by definition harmful to the Green Belt and should only be approved in very special circumstances. I have also found the proposal would result in some limited harm to openness. 27. Policy GB6.2 of the Framework specifies that substantial weight is given to any harm to the Green Belt, including harm to its openness and that very special circumstances will not exist unless the potential harm to the Green Belt is clearly outweighed by other considerations. This is a high hurdle for a development proposal to overcome. 28. In addition, I have found that the proposed development would have a harmful effect on the character and appearance of the host property and surrounding area. 29. A lack of identified planning harm with regards to ecology and the living conditions of neighbouring occupiers is of neutral weight in the balance. 30. The other considerations put forward in favour of the proposal only carry limited weight and, as such, do not clearly outweigh the harm identified; accordingly the very special circumstances needed to justify the development do not exist. The proposed development would, therefore, conflict with Policy QP 5 of the Local Plan, which seeks to protect Green Belt, unless very special circumstances are demonstrated. 31. The proposal would be contrary to the development plan and the Framework. For the reasons given above, and having had regard to other matters, I conclude that the appeal should be dismissed. S Ramsden INSPECTOR