94-96 Coppermill Road, Staines, TW19 5NS

94-96 Coppermill Road, Staines, TW19 5NS — Royal Borough of Windsor and Maidenhead — Appeal Decision Site visit made on 20 January 2026 by L Clark MSc MRTPI Decision by John Morrison BA (Hons) MSc MRTPI an Inspector appointed by the Secretary of State Decision date: 10 February 2026 Appeal Ref: APP/T0355/W/25/3374975 94-96 Coppermill Road, Wraysbury, Staines, Windsor and Maidenhead TW19 5NS • 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 A Soni against the decision of Royal Borough of Windsor and Maidenhead. • The application Ref is 25/01726. • The development proposed is ‘retention of existing single storey rear extension and outbuilding to the guest house use.’ Decision 1. The appeal is dismissed. Appeal Procedure 2. The site visit was undertaken by a representative of the Inspector whose recommendation is set out below and to which the Inspector has had regard before deciding the appeal. Preliminary Matters 3. The description above is taken from the application form which differs slightly from the decision notice. However, this has not changed anything fundamental nor prejudiced the ability of any party to make their case in respect of the appeal scheme.

94-96 Coppermill Road, Staines, TW19 5NS — Royal Borough of Windsor and Maidenhead — Appeal Decision At the time of the site visit, the extension and outbuilding had been constructed but the three sheds had not been demolished. 4. Having reviewed the submitted evidence, there are typing errors on the decision notice. The first is that it refers to the height of a boundary treatment but no such development forms part of the appeal. The second is with regard to the very special circumstances of the proposal and it should read “very special circumstances have not been demonstrated that would outweigh the harm.” Again, it is clear from the appellant’s case these typing errors have not changed anything fundamental nor prejudiced the ability of any party to make their case in respect of the appeal. Main Issues 5. The main issues are a) whether the scheme is inappropriate development in the Green Belt; b) its effect on the openness of the Green Belt; c) whether the development is at an unacceptable risk of flooding and d) if the scheme is inappropriate development, 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 it. https://www.gov.uk/planning-inspectorate

94-96 Coppermill Road, Staines, TW19 5NS — Royal Borough of Windsor and Maidenhead — Appeal Decision Appeal Decision APP/T0355/W/25/3374975 Reasons for the Recommendation Inappropriate Development 6. Policy QP5 of the Royal Borough of Windsor & Maidenhead Local Plan 2022 (LP) refers to the National Planning Policy Framework (the Framework) to ascertain what would be inappropriate development in the Green Belt. In paragraph 154 (c), The Framework states that disproportionate additions over and above the size of an original building are inappropriate development. It does not confirm what would be disproportionate and so it would be a matter of judgement. An outbuilding can be treated as an “extension” for the purposes of paragraph 154 (c) and whether a detached structure would amount to an extension of the existing building is a matter of fact and degree. The approach taken by the LP and as set out by the Framework, is to restrict the construction of new buildings in the interests of the Green Belt’s openness and permanence. 7. The appeal property was used as a guest house at the time of the site visit. It is large and sprawling with an equally substantial garden area having originally been two separate dwellings.

94-96 Coppermill Road, Staines, TW19 5NS — Royal Borough of Windsor and Maidenhead — Appeal Decision The original properties appear to have been much smaller in a fairly square shape and positioned alongside one another to the front of the site. The buildings have been subject to significant extensions and alterations to the rear including at first floor level along with an extension to join both together creating a substantial L-shape. There are also a number of other outbuildings in the garden. The one subject of this appeal is used as an office and is within close proximity of the main building with which it has a close relationship. I see no reason why I cannot therefore consider the outbuilding as an extension to the building in this case, for green belt purposes. 8. I agree that the extension and outbuilding subject of the appeal are comparatively small when compared to the other extensions at the property. Nevertheless, the Framework refers to the original building and therefore their overall size compared to the original must be considered. The extension does not project from the original building but rather a previously extended part.

94-96 Coppermill Road, Staines, TW19 5NS — Royal Borough of Windsor and Maidenhead — Appeal Decision Taking into account the floor space and volume of all of the outbuildings and extensions over the original, it is very evident that growth of some significance substance has occurred. Therefore, the development represents disproportionate additions over and above the original such that it is inappropriate development in the Green Belt. The scheme therefore conflicts with the position of the Framework and Policy QP5 of the LP. Openness 9. One of the essential characteristics of the Green Belt is its openness which, it has been established, has a visual and spatial aspect. The latter can be taken to mean the absence of built form. The development is screened from wider views due to the layout of the site and therefore the effect on the visual aspect is limited. Nevertheless, the works take up substantial space where there was no built form prior and would therefore, unavoidably, reduce the spatial aspect of the Green Belt’s openness. 10. Even if the sheds were to be demolished, the land take in built form overall of the extension and outbuilding would still exceed that to be removed.

94-96 Coppermill Road, Staines, TW19 5NS — Royal Borough of Windsor and Maidenhead — Appeal Decision Even if that were not the case, having regard to the materially different composition and permanency of the development compared to that being demolished, there would still be an unacceptable loss of openness in overall presence and space terms. This would be https://www.gov.uk/planning-inspectorate 2

94-96 Coppermill Road, Staines, TW19 5NS — Royal Borough of Windsor and Maidenhead — Appeal Decision Even if that were not the case, having regard to the materially different composition and permanency of the development compared to that being demolished, there would still be an unacceptable loss of openness in overall presence and space terms. This would be https://www.gov.uk/planning-inspectorate 2

94-96 Coppermill Road, Staines, TW19 5NS — Royal Borough of Windsor and Maidenhead — Appeal Decision Appeal Decision APP/T0355/W/25/3374975 in further conflict with the position of the Framework, and the aims of Policy QP5 of the LP. Flood Risk 11. The Framework requires that a site-specific flood risk assessment should be provided for all development in Flood Zone 2 and such has not been provided. I have no evidence before me of any mitigation that has taken place given the retrospective nature of the appeal. I could not impose a planning condition to request a flood risk assessment after planning permission is granted because it could affect the details of the development. Insofar as there being potentially some works in place of where further investigation might be required. 12. Given the lack of a flood risk assessment, I cannot be sufficiently confident that there would not be an increased flood risk as a result of the proposal. Either on the appeal site or elsewhere, despite it being potentially sequentially appropriate as it is an extension to an existing use. Therefore, there would be conflict with Policy NR1 of the LP which is concerned with managing flood risk amongst other things, as well as the aims of the Framework in the same regard. Other Considerations 13.

94-96 Coppermill Road, Staines, TW19 5NS — Royal Borough of Windsor and Maidenhead — Appeal Decision The demolition of the sheds to effectively ‘trade off’ against the development subject of the appeal appears to be, for the appellant, on a comparison of their sizes. However, I remain to be convinced of that point given the totality of the alterations over the original buildings and further it is unlikely that the sheds formed part of the original dwelling for the Framework’s purposes. I therefore attach limited weight to the trade-off situation. 14. A lack of harm with regard to the use of matching materials therefore preserving the character and appearance of the area would be neutral and as such would not weigh in favour of the appeal scheme. Similarly, the use of the extension as visitor accommodation to the area would be of benefit economically, but worthy of limited weight given I am uncertain of what difference the space would make in that respect and/or whether there is a specific need for it in essential terms. I remain to be convinced that the dining area and office could not be provided in another way. 15. The examples provided are not easily comparable to the appeal scheme.

94-96 Coppermill Road, Staines, TW19 5NS — Royal Borough of Windsor and Maidenhead — Appeal Decision One relates to a rear extension that was approved under the prior approval regime, and the others relate to smaller scale extensions when compared to the vast extensions and alterations that have taken place to the original buildings at the appeal site. Conclusion and Recommendation 16. There would be harm to the Green Belt by virtue of the appeal scheme being inappropriate development and unacceptably reducing openness. This attracts substantial weight. Furthermore, I have not been provided with any evidence to show that the development is safe from flooding. I have reviewed the other considerations advanced and, for the reasons I have set out, they would not attract sufficient weight to clearly outweigh the harms I have found. Such that the very special circumstances needed to justify the appeal scheme do not exist. Material considerations do not therefore indicate that a decision should be made other than in accordance with the development plan, with which there would be multiple https://www.gov.uk/planning-inspectorate 3

94-96 Coppermill Road, Staines, TW19 5NS — Royal Borough of Windsor and Maidenhead — Appeal Decision Appeal Decision APP/T0355/W/25/3374975 conflicts for the reasons I have given and therefore I am led to recommending the appeal is dismissed.

94-96 Coppermill Road, Staines, TW19 5NS — Royal Borough of Windsor and Maidenhead — L Clark APPEAL PLANNING OFFICER Inspector’s Decision 17. I have considered all the submitted evidence and my representative’s report and on that basis the appeal is dismissed.

94-96 Coppermill Road, Staines, TW19 5NS — Royal Borough of Windsor and Maidenhead — John Morrison INSPECTOR https://www.gov.uk/planning-inspectorate 4