69 Chertsey Lane, Staines upon Thames, Surrey, TW18 3LA

69 Chertsey Lane, Staines upon Thames, Surrey, TW18 3LA — Runnymede Borough Council — Appeal Decision Site visit made on 1 July 2025 by A Wright BSc (Hons) MRTPI an Inspector appointed by the Secretary of State Decision date: 10 July 2025 Appeal Ref: APP/Q3630/W/25/3361851 69 Chertsey Lane, Staines-upon-Thames, Surrey TW18 3LA • 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 Dr Haifaa Nasir against the decision of Runnymede Borough Council. • The application Ref is RU.24/0091. • The development proposed is described as ‘change of use from office to residential dwelling’. Decision 1. The appeal is dismissed. Preliminary Matters 2. The building has already been converted and extended. These works differ to those shown on the proposed plans, including a slightly larger extension and different window and door openings. I have determined the appeal based on the submitted plans considered by the Council and have assessed the effect that the proposal would have rather than the effect that the current building is having. 3. The submitted plans do not clearly show the proposed room layout for the new dwelling.

69 Chertsey Lane, Staines upon Thames, Surrey, TW18 3LA — Runnymede Borough Council — Appeal Decision As such, I am not able to assess whether the proposal would provide acceptable outlook and internal space for future occupiers of the property. Nevertheless, this has not hampered my ability to determine the appeal overall. Main Issues 4. The main issues in this appeal are: • whether the proposed development would be in a suitable location, with reference to policies concerned with development in areas at risk of flooding; • whether the proposed scheme would provide acceptable living conditions for future occupiers, with particular regard to the provision of external amenity space; and • the effect of the proposal on the character and appearance of the area. Reasons Flood risk 5. The National Planning Policy Framework 2024 (the Framework) states that inappropriate development in areas at high risk of flooding should be avoided by directing development away from areas at highest risk. A site-specific flood risk assessment (FRA) should be provided for all development in flood zones 2 and 3, https://www.gov.uk/planning-inspectorate

69 Chertsey Lane, Staines upon Thames, Surrey, TW18 3LA — Runnymede Borough Council — Appeal Decision Appeal Decision APP/Q3630/W/25/3361851 which should include demonstration of safe access and escape routes where appropriate. Policy EE13 of the Runnymede 2030 Local Plan (LP) also sets out when FRAs are required and the need to address managing flood risk over the lifetime of the development. 6. The Environment Agency’s flood map indicates that the site is within flood zone 3, meaning it is at greater than 1% risk of flooding from fluvial sources due to its proximity to the River Thames. Based on the Runnymede SFRA 2018, the Council’s interactive mapping shows the site within flood zone 3b, the functional floodplain. However, the Planning Practice Guidance (PPG) has since redefined flood zone 3b to include land with a 3.3% or greater annual probability of flooding1. 7. The Lower Thames Model 2019 (LTM) models the 3.3% annual exceedance probability (AEP) event. Based on the lowest existing ground level at the proposed development location and potential flood depths in this scenario, the FRA concludes that the proposed development would lie in flood zone 3b using the current definition in the PPG.

69 Chertsey Lane, Staines upon Thames, Surrey, TW18 3LA — Runnymede Borough Council — Appeal Decision This means that it would be within the functional floodplain where more vulnerable development including dwellinghouses should not be permitted2. 8. As the proposal is for residential use with a development lifetime of 100 years, the FRA considers the implications of a 1% AEP plus 35% climate change event. The LTM indicates that flood depths on the site could range up to 0.87m in this event. Using the Environment Agency’s approach, this scenario carries a significant hazard rating, and the FRA states that safe access and egress from the site may not be possible in this event. 9. In addition, the FRA indicates that groundwater levels are likely to respond to variations in the water level of the River Thames nearby. Therefore, the site is susceptible to groundwater flooding linked to fluvial flooding. 10. The proposed development would not increase the built footprint and as such should not increase flood risk elsewhere. There would also be a low risk of flooding from tidal sources, canals, surface water, reservoirs and sewers. The FRA recommends incorporating flood resilience and resistance measures, providing any sleeping accommodation on the highest floor available and signing up to the local flood warning service. 11.

69 Chertsey Lane, Staines upon Thames, Surrey, TW18 3LA — Runnymede Borough Council — Appeal Decision Nonetheless, the site is at high risk from fluvial and groundwater flooding, and safe access and escape routes to reach land outside the flooded area using public rights of way without the intervention of emergency services or others would not be achievable in the 1% AEP plus 35% climate change event. Therefore, the proposed scheme would unacceptably increase the number of people at risk from flooding during the lifetime of the development. 12. A suitably worded condition would ensure implementation of the flood risk mitigation measures set out in the FRA. However, as it has not been demonstrated that safe access and escape routes would be achieved, it would not be reasonable to impose a pre-commencement condition in this respect. 13. Consequently, the proposed development would not be in a suitable location, with reference to policies concerned with development in areas at risk of flooding. This 1 Paragraph: 078 Reference ID: 7-078-20220825 2 PPG Paragraph: 079 Reference ID: 7-079-20220825 and Annex 3 of the Framework https://www.gov.uk/planning-inspectorate 2

69 Chertsey Lane, Staines upon Thames, Surrey, TW18 3LA — Runnymede Borough Council — Appeal Decision Appeal Decision APP/Q3630/W/25/3361851 would be contrary to Policy EE13 of the LP and the Framework’s requirements in respect of flood risk. Living conditions 14. Policy EE1 of the LP does not set out the amount of outdoor space which should be provided, but it requires provision of an appropriate standard of private amenity space. Further, the Runnymede Design SPD 2021 requires all dwellings to be designed with high quality, usable external space to accommodate different lifestyles and a range of private and communal activities. 15. The proposal would not include any provision for external space for the occupiers of the new residential unit. As such, future residents would not have access to any outside area for important household functions such as sitting out, drying clothes or pursuing outdoor domestic leisure activities. Although the property may not be occupied by a family, the absence of any outdoor space would create an unsatisfactory living environment for its occupants. 16. Therefore, I conclude that the proposed scheme would provide unacceptable living conditions for future occupiers, with particular regard to the provision of external amenity space. This would be contrary to Policy EE1 of the LP.

69 Chertsey Lane, Staines upon Thames, Surrey, TW18 3LA — Runnymede Borough Council — Appeal Decision Character and appearance 17. The site comprises a large outbuilding in the grounds of a detached house amongst a row of properties facing the River Thames. It lies at the end of an access road between houses on Chertsey Lane, along which lie various sizeable outbuildings and a dwelling. Therefore, the local character consists of dwellings facing the river and Chertsey Lane with many substantial buildings between. 18. The proposal is to convert and extend parts of the existing outbuilding. The Council and the appellant do not dispute that the external appearance of the proposed building would be acceptable. As it is not proposed to enclose or subdivide the plot from the host dwelling at 69 Chertsey Lane, the proposed development would not appear cramped nor incompatible with the existing urban grain. Therefore, even though the structure would function as a separate dwelling, it would appear as one of various buildings which prevail along the access road. 19. An additional dwelling would create the potential for greater activity around the building, including more vehicular and pedestrian movements.

69 Chertsey Lane, Staines upon Thames, Surrey, TW18 3LA — Runnymede Borough Council — Appeal Decision However, the Council accepts that the proposed unit would not increase the number of comings and goings at the property demonstrably over and above that which exists. 20. Consequently, I conclude that the proposal would not harm the character and appearance of the area. This would comply with Policy EE1 of the LP where it requires proposals to respond to the local context. Other Matters 21. The Council accepts that it cannot currently demonstrate a five year housing land supply required by the Framework. This triggers the circumstances in paragraph 11(d) of the Framework. However, the proposal would be within an area at risk of flooding which provides a strong reason for refusing the development proposed in accordance with paragraph 11(d)(i). Consequently, the presumption in favour of sustainable development is not engaged. https://www.gov.uk/planning-inspectorate 3

69 Chertsey Lane, Staines upon Thames, Surrey, TW18 3LA — Runnymede Borough Council — Appeal Decision Appeal Decision APP/Q3630/W/25/3361851 22. The Council did not find harm or development plan conflict in relation to several other matters, including biodiversity. However, even if I were to agree with the Council on this point, the absence of harm would be a neutral matter which would not carry weight in favour of the proposal. Planning Balance and Conclusion 23. Even if the scheme provided acceptable outlook and internal space for occupants of the dwelling, the proposed development is not in a suitable location with reference to policies concerned with development in areas at risk of flooding. It would also provide unacceptable living conditions for future occupiers with regard to the provision of external amenity space. 24. For the above reasons, the proposal conflicts with the development plan and the material considerations, including the Framework, do not indicate that the appeal should be decided other than in accordance with it. Therefore, the appeal should be dismissed.

69 Chertsey Lane, Staines upon Thames, Surrey, TW18 3LA — Runnymede Borough Council — A Wright INSPECTOR https://www.gov.uk/planning-inspectorate 4