Upgrading appearance of existing detached dwelling incorporating front and side extensions and loft conversion with front and rear dormer windows to provide accommodation within loft space (alternative to extension works granted under references DC/21/05285/PLUD & DC/23/02593/PLUD)

Appeal Decision by R Cahalane BA(Hons) MSc MRTPI an Inspector appointed by the Secretary of State Decision date: 4th March 2026 Appeal Ref: 6001357 26 Standard Road, Downe, Orpington, Bromley BR6 7HL • 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 & Mrs J Keys against the decision of the Council of the London Borough of Bromley. • The application Ref is 25/01852/FULL6. • The development proposed was described as: “upgrading appearance of existing detached dwelling incorporating front and side extensions and loft conversion with front and rear dormer windows to provide accommodation within loft space (alternative to extension works granted under references DC/21/05285/PLUD & DC/23/02593/PLUD).” Decision 1. The appeal is allowed and planning permission is granted for upgrading appearance of existing detached dwelling incorporating front and side extensions and loft conversion with front and rear dormer windows to provide accommodation within loft space at 26 Standard Road, Downe Orpington, Bromley BR6 7HL in accordance with the terms of the application, Ref 25/01852/FULL6, and the plans submitted with it, subject to the conditions in the attached schedule. Preliminary Matters 2. In my above decision, I have utilised the description of development from the application form rather than the decision notice, as that is what the appellants applied for, and it accurately describes the proposal. I have deleted reference to the proposal being an alternative to extension works previously granted permission, as that is superfluous detail. 3. Although not explicitly cited in the reasons for refusal, the officer report refers to a likely loss of light to the occupiers of No.30 Standard Road. This therefore forms an additional consideration for this appeal. Main Issues 4. In light of the above, the main issues are: • whether the proposal is inappropriate development in the Green Belt having regard to the National Planning Policy Framework (the Framework) and relevant development plan polices; • the effect of the proposal on the openness and purposes of the Green Belt; • the effect on the character and appearance of the host dwelling and the surrounding area; • the effect on the living conditions of No 30 Standard Road, with particular regard to outlook and light; and Appeal Decision 6001357 2 • whether any harm by reason of inappropriateness, and any other harm, would be clearly outweighed by other considerations so as to amount to very special circumstances required to justify the proposal. Reasons Whether inappropriate development 5. The appeal site (No 26) comprises a detached bungalow, located within the Green Belt as designated on the Policies Map of the Council’s Local Plan (LP) (adopted 2019). Policy 49 of the LP is consistent with the Framework insofar as it sets out that apart from a number of exceptions, the construction of new buildings in the Green Belt is inappropriate. Permission will not be given for inappropriate development unless very special circumstances can be demonstrated that clearly outweigh the harm by reason of inappropriateness or any other harm. 6. One such exception 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. LP Policy 51 provides further detail in respect of extensions or alterations to dwellinghouses in the Green Belt. Such development will only be permitted if, among other things, the net increase in the floor area over that of the original dwellinghouse is no more than 10%, as ascertained by external measurement. 7. The glossary to the LP does not provide a definition of what constitutes an “original dwellinghouse”. The Framework however defines this as “a building as it existed on 1 July 1948 or, if constructed after 1 July 1948, as it was built originally.” The evidence before me, including my site visit observations, does not indicate that the original dwellinghouse of No 26 has been substantially extended. As set out in the officer report, the total existing footprint of No 26 is 94.2sqm, which the appellants have not disputed, and which I have no reason to dispute either. 8. The main parties agree that the proposed footprint would be 159.3sqm and that the proposed floor area would be 246.1sqm. No existing floor area or volume figures are before me and there would be no increase beyond the existing rear elevation of No 26. However, it is self-evident that the proposal would form a significant increase both in terms of footprint and overall size of built form, and which would be substantially in excess of what is supported under LP Policy 51. 9. Such an increase in overall size would amount to a disproportionate addition over and above the size of the original form of No 26. The increased built form would be visible from surrounding vantage points. In both spatial and visual terms, the proposal would thus have a greater impact on the openness of the Green Belt than the existing situation. Whilst the overall harm in this regard would be moderate, this would be contrary to the Framework where it states that an essential characteristic of Green Belts is their openness. 10. I therefore conclude that the proposal is inappropriate development in the Green Belt having regard to the Framework and Policies 49 and 51 of the LP. In this respect, the scheme also conflicts with Policy G2 of the London Plan which states that the Green Belt should be protected from inappropriate development. Character and appearance 11. No 26 is notably more set back from the road and of lower height than the dwellings to each side. The proposal involves comprehensive extensions, namely in respect Appeal Decision 6001357 3 of the front extensions and roof alterations. This would result in a substantial increase in scale and bulk, visible from the street, and would fundamentally alter the existing simple and low-key architectural form of No 26. The resultant non- subservient form would be contrary to the guidance within the Council’s Urban Design Guide Supplementary Planning Document (SPD) (adopted 2023). 12. However, there is a wide variety of dwelling styles, ages and sizes in the vicinity along Standard Road, including roof forms, with several nearby examples of front dormers and front gable ends. In this context, the proposed extensions would not appear incongruous or uncharacteristically large. 13. The proposed front projections would erode the space to the front of No 26, but would be broadly in line with the neighbouring frontmost elevations to each side. These two storey additions would not be sited closer to the side boundaries than the existing elevations. The above factors would avoid the plot appearing overdeveloped or cramped in appearance. 14. I therefore conclude that the proposal would not harm the character and appearance of No 26 and the surrounding area. In this respect, the scheme would comply with Policies 6 and 37 of the LP, and Policy D3 of the London Plan. These policies require, amongst other things, extensions to complement and be compatible with development in the surrounding area in terms of scale, form and layout, maintain space or gaps between buildings, and to be of a high standard of design and layout. 15. Although the proposal is non-subservient to No 26, it would otherwise meet the relevant SPD guidance in terms of adopting an appropriate design approach and avoiding a detrimental impact on character. As subservience to an existing building is not a requirement of LP Policies 6 and 37 or London Plan Policy D3, I afford limited weight to this specific conflict with the SPD. Moreover, such conflict with this guidance does not amount to conflict with the development plan. Living conditions – No 30 Standard Road 16. The proposed two-storey front extension would project beyond the nearest single storey front elevation of No 30, which contains a habitable room window on its front elevation. However, the separation distances are such that there would be no breach of a 45-degree line of sight taken from this neighbouring window towards the proposal. No 30 is also on slightly higher ground level, and the proposed chalet- style pitched roof form would somewhat reduce the projecting bulk of the extension. 17. The above factors would avoid a harmful impact on the living conditions of No 30 in terms of outlook and daylight. The orientation of the proposal northwest of No 30 would also avoid a harmful degree of sunlight loss to this neighbour. 18. The proposal would therefore not harm the living conditions of No 30 Standard Road in terms of outlook and light. There is thus no conflict with Policy 37 of the LP insofar as it requires development proposals to respect the amenity of occupiers of neighbouring buildings, provide healthy environments and ensure no harm in terms of inadequate daylight or overshadowing. 19. The second reason for refusal cites conflict with the SPD. However, the evidence before me does not indicate any specific conflict with this guidance in respect of living conditions. Appeal Decision 6001357 4 Other considerations 20. My attention has been drawn to a previously granted prior approval and previous lawful development certificates for side, rear and roof extensions to No 26. It is put to me that these lawful extensions could be constructed as an alternative to the proposal subject of this appeal. Caselaw has held that that there should be a “real prospect” of a fallback development being implemented1, and that such a prospect does not have to be probable or even have a high chance of occurring; it has to be only more than a merely theoretical prospect2. 21. The main parties agree that the gross internal floor area of the appeal scheme would be some 6% higher than the lawful fallback floor area. However, more significantly, the external footprint of the appeal proposal would be 9.9% less than the lawful fallback footprint, and the current proposed external volume would be some 2% lower. 22. Although the lawful extensions are not directly comparable to the appeal proposal in terms of positioning and internal layout, the appellants clearly intend to provide additional space for their needs and their family’s needs. Thus, I have no reason to dispute that there is a real prospect of these lawful extensions being implemented if this appeal were to be dismissed, and this is beyond a theoretical prospect. 23. Allowing this appeal as an alternative to the lawful fallback extensions would reduce the impact on the openness of the Green Belt, and would also enable the rear garden area to be retained. The above issues therefore form matters in which I can attach considerable positive weight to. Green Belt Balance 24. For the above reasons, the proposal is inappropriate development in the Green Belt that is, by definition, harmful to the Green Belt. The impact on the Green Belt in spatial and visual terms would be moderate and would harm the openness of the Green Belt. The Framework requires substantial weight to be attached to any harm to the Green Belt. There is sufficient conflict with LP Policies 49 and 51 arising from this harm that amounts to conflict with the development plan as a whole. 25. LP Policies 49 and 51, along with the Framework, set out that very special circumstances 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 have found no other harm arising from the appeal scheme, including the character and appearance of No 26 and the surrounding area, and the living conditions of No 30. The lack of harms in these respects neither weigh in favour nor against allowing this appeal. 26. However, in the particular circumstances of this appeal, I have found that the other considerations clearly outweigh the Green Belt harm that would occur. This is because the permitted development fallbacks would, if implemented, lead to additional harm to openness beyond that which I have identified, and a significant reduction in rear garden space. Looking at the case as a whole, very special circumstances exist which justify the appeal development. 1 Mansell v Tonbridge and Malling Borough Council & others [2017] EWCA Civ 1314 2 Schneck v SSHCLG & West Berkshire District Council [2022] EWHC 3335 (Admin) Appeal Decision 6001357 5 Conditions 27. Condition 1 is necessary in the interests of planning certainty. Condition 2 is necessary to clarify the approved plan details. As the proposed elevations plan includes external materials, a further condition governing that is not necessary. 28. I have considered the Council’s suggested additional conditions against the tests set out in the Framework and Planning Practice Guidance (PPG), and have amended their wording where necessary. As No 26’s land level is higher than the highway, it is necessary and reasonable to impose a condition (No 3) governing surface water drainage details. As the proposal relates to extensions to an existing dwelling, a pre-occupation trigger would be unreasonable and is thus deleted. 29. As the proposed plans already show an area of off-street parking, and in the absence of an objection from the Council’s Highway Development Engineer, a condition requiring additional details is not necessary. Given the householder scale of development, a condition governing the condition of Standard Road before and after development is not commensurate to the scale of development, and is thus unreasonable. For the same reason, it would be unreasonable to impose a condition requiring a Construction Management Plan. Hours of construction works would be governed by separate environmental health legislation. 30. The appellants indicated that they would be willing to forego their permitted development (PD) rights should the appeal be allowed. The Framework and PPG state that planning conditions should not be used to restrict PD rights unless there is clear justification to do so, and that such conditions may not pass the test of reasonableness or necessity. 31. I am aware that a planning permission can only be revoked by the Secretary of State following the process set out under sections 97 and 100 of the Act. However, the alternative fallback schemes before me relate to permitted development rather than development subject to the permission types referred to in section 97(1). 32. Condition 4 can therefore be imposed to restrict the implementation of the development allowed under this appeal in conjunction with or subsequent to the implementation of any development permitted by virtue of Classes A, B and D of Part 1 of Schedule 2 to the Town and Country Planning (General Permitted Development) (England) Order 2015 (or any order revoking and re-enacting that Order with or without modification). This condition is necessary to preserve the openness of the Green Belt. 33. In this case, the size and location of the proposal provide clear justification for removal of PD rights for extensions, roof extensions and porches to No 26 (condition 5). This is necessary in order to retain sufficient off-street parking space and to preserve the openness of the Green Belt. Conclusion 34. For the above reasons, the appeal is allowed. R Cahalane INSPECTOR Appeal Decision 6001357 6 Schedule of Conditions 1) The development hereby permitted shall begin not later than three years from the date of this decision. 2) The development hereby permitted shall be carried out in accordance with the following approved plans: Drawing Nos 9069-PD-03 Rev D; 9069-PD-04 Rev D. 3) Prior to the commencement of above ground development hereby permitted, details of the drainage system for surface water drainage to prevent the discharge of surface water from No 26 Standard Road on to the highway shall be submitted to and approved in writing by the Local Planning Authority. The approved drainage system shall be completed in accordance with the details approved and shall be retained permanently thereafter. 4) The development hereby permitted shall not be implemented in conjunction with or subsequent to the implementation of any development permitted by virtue of Classes A, B and D of Part 1 of Schedule 2 to the Town and Country Planning (General Permitted Development) (England) Order 2015 (or any order revoking and re-enacting that Order with or without modification). 5) Notwithstanding the provisions of the Town and Country Planning (General Permitted Development) (England) Order 2015 (or any order revoking and re- enacting that Order with or without modification), no development permitted by virtue of Classes A, B and D of Part 1 of Schedule 2 to the Order shall be undertaken. ***End of Schedule***