12 Great Central Avenue , Ruislip, HA4 6UD

12 Great Central Avenue , Ruislip, HA4 6UD — London Borough of Hillingdon — Appeal Decision Site visit made on 15 July 2025 by Jonathan Edwards BSc(Hons) DipTP MRTPI an Inspector appointed by the Secretary of State Decision date: 23rd July 2025 Appeal Ref: APP/R5510/W/25/3359178 12 Great Central Avenue, Ruislip HA4 6UD • The appeal is made under section 78 of the Town and Country Planning Act 1990 (as amended) against a refusal to grant outline planning permission. • The appeal is made by Mavadia Estate Ltd against the decision of the Council of the London Borough of Hillingdon. • The application Ref is 78809/APP/2024/1425. • The development proposed is demolition of existing bungalow and ancillary building and erection of a detached 2-storey dwelling and separate apartment block containing 4 units. Decision 1. The appeal is dismissed. Preliminary Matters 2. As well as this appeal, I have also determined a separate appeal (reference number APP/R5510/W/25/3361277). This relates to the same site but it seeks permission in principle for the demolition of the existing bungalow and ancillary building and erection of a residential development comprising between 2 and 4 units. This other appeal is the subject of a separate decision notice. 3. This appeal seeks outline planning permission.

12 Great Central Avenue , Ruislip, HA4 6UD — London Borough of Hillingdon — Appeal Decision Approval is sought for details of access, layout and scale with details of landscaping and appearance reserved for future consideration. I have treated details on the plans that relate to the appearance of the proposed buildings and the internal room layouts as being submitted for illustrative purposes only. 4. Plans that show minor amendments to the internal room layouts of the proposed units have been provided. These were not with the Council at the time it made its decision but it has had the opportunity to comment on the revisions. The amendments do not fundamentally change the proposal. As such, no injustice would be caused by considering the amended drawings in my assessment. 5. A revised version of the National Planning Policy Framework (the Framework) has been issued since the Council’s decision. I have had regard to this in my consideration of the appeal. Main Issues 6.

12 Great Central Avenue , Ruislip, HA4 6UD — London Borough of Hillingdon — Appeal Decision The main issues are (i) the effect of the development on the character and appearance of the area, (ii) whether it would provide an appropriate housing mix, (iii) whether it would provide suitable living conditions for future residents, (iv) its effect on biodiversity and trees, (v) the effect on air quality, and (vi) the effect on living conditions at adjoining residences at 14 Great Central Avenue (No 14). https://www.gov.uk/planning-inspectorate

12 Great Central Avenue , Ruislip, HA4 6UD — London Borough of Hillingdon — Appeal Decision The main issues are (i) the effect of the development on the character and appearance of the area, (ii) whether it would provide an appropriate housing mix, (iii) whether it would provide suitable living conditions for future residents, (iv) its effect on biodiversity and trees, (v) the effect on air quality, and (vi) the effect on living conditions at adjoining residences at 14 Great Central Avenue (No 14). https://www.gov.uk/planning-inspectorate

12 Great Central Avenue , Ruislip, HA4 6UD — London Borough of Hillingdon — Appeal Decision Appeal Decision APP/R5510/W/25/3359178 Reasons Character and appearance. 7. The existing bungalow faces Great Central Avenue with a side boundary next to the pavement on Primrose Gardens. The dwellings in the surrounding area vary in appearance, although most are of typical domestic scale with pitched roofs. Near to the site is Great Central House, a former office building that has been converted to flats. This is a much wider and taller property than the adjoining residences but it is read as part of the adjacent local centre rather than part of the residential suburban area surrounding the appeal site. 8. Dwellings on Great Central Avenue and Primrose Gardens tend to be set back from the road so as to avoid a overly dominant influence on the street scene. At odds with the general development pattern, the side elevation of the bungalow on the appeal site is quite close to the pavement on Primrose Gardens. However, it does not appear unusually prominent as it has low eaves and a hipped roof that slopes up and away from the side boundary. 9.

12 Great Central Avenue , Ruislip, HA4 6UD — London Borough of Hillingdon — Appeal Decision The proposed apartment building would be positioned a similar distance from Primrose Gardens compared to the bungalow but it would be much wider and taller with eaves above first floor windows. The full size of this elevation would be appreciated from the public highway as it would be on an exposed corner plot. Moreover, while the apartment block would have a sloped roof, the plans indicate that this would be a significant size as it would have a large flat roof area rather than a ridgeline as seen at most other local houses. By reason of its scale and close proximity to Primrose Gardens, the apartment building would appear unusually bulky and prominent. 10. The proposed dwelling would face Primrose Gardens. It would be a similar size to the adjoining property and it would be set back from the pavement to follow the established building line. However, the house and the apartment building when considered together would cover a large part of the appeal site. From Primrose Gardens the large side elevation of the apartment building would be seen next to the proposed dwelling with only a small space in between.

12 Great Central Avenue , Ruislip, HA4 6UD — London Borough of Hillingdon — Appeal Decision This view would emphasise the unusual bulk of the apartment building as well as the loss of openness currently provided for by the back garden to the bungalow. As a consequence, the development would look cramped within the site. 11. When seen from Great Central Avenue, the apartment building would appear similar in height and width to the adjoining properties and it would be a similar distance back from the road. Also, windows could be provided in the elevations of the buildings facing onto Primrose Gardens to increase overlooking of the street compared to the existing situation. Through the reserved matters process, the Council could ensure the buildings include materials and architectural features that would be appropriate to the area. However, acceptability of the proposal in these respects would not overcome nor address the unsympathetic layout and scale of the development, particularly when viewed from Primrose Gardens. 12. For these reasons, I conclude the development would harm the character and appearance of the area.

12 Great Central Avenue , Ruislip, HA4 6UD — London Borough of Hillingdon — Appeal Decision In these regards, it would not accord with policy BE1 of the Council’s Local Plan Part 1 adopted 2012 (LP1), policies DMHB11 and DMHB12 of the Council’s Local Plan Part 2 Development Management Policies adopted 2020 (LP2) and policy D3 of the London Plan 2021 (LonP). Amongst https://www.gov.uk/planning-inspectorate 2

12 Great Central Avenue , Ruislip, HA4 6UD — London Borough of Hillingdon — Appeal Decision In these regards, it would not accord with policy BE1 of the Council’s Local Plan Part 1 adopted 2012 (LP1), policies DMHB11 and DMHB12 of the Council’s Local Plan Part 2 Development Management Policies adopted 2020 (LP2) and policy D3 of the London Plan 2021 (LonP). Amongst https://www.gov.uk/planning-inspectorate 2

12 Great Central Avenue , Ruislip, HA4 6UD — London Borough of Hillingdon — Appeal Decision Appeal Decision APP/R5510/W/25/3359178 other things, these seek to ensure development integrates with the surrounding area, particularly in terms of scale. The Council’s refusal reason on this matter refers to LonP policy D6 but this contains no provisions relevant to this issue. Housing mix. 13. LP2 policy DMH2 requires a mix of units of different sizes within residential developments. The paragraph in LP2 before this policy explains that current information on housing need indicates a requirement for larger 3 bedroom properties. LonP policy H10 states that schemes should generally consist of a range of unit sizes, although the appropriate mix should be influenced by various factors. These include the nature and location of the site with a higher proportion of 1 and 2 bedroom units generally being more suitable on sites close to a station. LonP policy H10 also highlights the role that 1 and 2 bedroom units have in freeing up existing family housing. 14. All of the proposed units are shown as having 2 bedrooms and so the development would not provide a mix of unit sizes. Also, it would not help address the identified need for 3 bedroom properties.

12 Great Central Avenue , Ruislip, HA4 6UD — London Borough of Hillingdon — Appeal Decision The site is close to South Ruislip Station and so having regard to LonP policy H10 it is located where 1 or 2 bedroom residences would be more appropriate. The development may also lead to larger houses being freed up through downsizing. Nonetheless, these factors fail to justify the narrow range of unit sizes as proposed and the complete absence of 3 bedroom dwellings given the identified need. Therefore, I conclude the development would provide an unacceptable mix of housing contrary to the provisions of LP2 policy DMH2 and LonP policy H10. Whether the development would provide suitable living conditions for future occupiers. 15. LP2 policy DMHB18 requires all new residential development to provide good quality and useable private outdoor amenity space in accordance with standards set out in table 5.3. These require a minimum 25m2 of private garden area for a 2 bedroom flat and 60m2 for a 2 bedroom house. LonP policy D6 sets lower minimum requirements for private outdoor space but this only applies where there are no higher standards in London borough councils’ development plan documents. Therefore, I attach greater weight to the requirements of LP2 policy DMHB18 in the assessment of the appeal scheme. 16.

12 Great Central Avenue , Ruislip, HA4 6UD — London Borough of Hillingdon — Appeal Decision The 2 ground floor apartments would each have garden space to the front and rear and the Council accepts that the total area for each would be in excess of the 25m2 standard. However, the front gardens would be small areas near to the apartment building front wall. Also, it is likely roadside boundary features would be needed to provide a suitable level of privacy. As such, the front gardens would feel enclosed. The back gardens would lie in the narrow gap between the proposed apartment building and the dwelling. The height of these buildings would have a significant overbearing effect on the gardens so as to limit their attractiveness for sitting outdoors and outdoor recreation. Therefore, the gardens to serve the ground floor apartments would not be of good quality. 17. The appellant has not sought to dispute the Council’s claim that the roof terraces to serve each of the upper floor apartments would measure 11m2 so below the 25m2 requirement for 2 bedroom flats. The appellant contends that the LP2 standard for private outdoor space to serve flats is impractical and highly unusual. They also point out other nearby flats that have smaller balconies. Nonetheless, https://www.gov.uk/planning-inspectorate 3

12 Great Central Avenue , Ruislip, HA4 6UD — London Borough of Hillingdon — Appeal Decision Appeal Decision APP/R5510/W/25/3359178 the outdoor areas to serve the upper apartments would fail to meet the table 5.3 standards and so they would be unacceptable in terms of LP2 policy DMHB18. 18. The garden associated with the 2 bedroom dwelling would consist of an area to the front as well as narrow strips of land to the side and rear. As a result, the useability of the garden would be highly restricted and it would be well below the 60m2 standard. The failure to provide sufficient and good quality garden space for the occupants of the development as a whole would not be addressed through public open space being within a reasonable walking distance from the site. 19. The parties disagree as to whether the revised room layout drawings show the development would meet internal floorspace standards as set out in Table 3.1 under LonP policy D6. However, I am satisfied a planning condition could be imposed to ensure each of the units complies with the standards. The plans indicate all the units would be dual aspect and so I envisage the rooms and windows in the ground floor apartments could be arranged to ensure occupiers would have adequate outlook and access to light.

12 Great Central Avenue , Ruislip, HA4 6UD — London Borough of Hillingdon — Appeal Decision Acceptable internal living environments could be secured through the reserved matters process when details on the size and the position of windows will be submitted for consideration. Also, a condition could be imposed on any planning permission that requires the approval of internal room layouts to ensure the level of light within each room is appropriate having regard to its purpose. Therefore, I conclude the development would provide satisfactory internal living environments for future occupants. In these respects, it would accord with LP2 policy DMHB16 and policy D6 of the LonP. 20. However, for the above reasons, I conclude the development would not provide suitable living conditions for residents as it would not include sufficient good quality outdoor private amenity spaces. In these respects, it would not accord with LP2 policy DMHB18. The Council’s refusal reason on this matter also refers to LP2 policy DMHB11 and LP1 policy BE1 but these contain no provisions on this matter. Biodiversity. 21. Schedule 7A of the Town and Country Planning Act 1990 (as amended) introduces a statutory framework for biodiversity net gain (BNG).

12 Great Central Avenue , Ruislip, HA4 6UD — London Borough of Hillingdon — Appeal Decision Unless exempt, the proposed development would be subject to the mandatory BNG condition that requires a BNG of at least 10%. 22. The application form states the BNG condition would not apply with reference to the temporary exemption for non-major developments and as the application seeks outline planning permission. However, the application is dated 24 May 2024 and so after the 2 April 2024 when the temporary exemption for non-major development ceased to apply. Moreover, there is no indication within the Biodiversity Gain Requirements (Exemptions) Regulations 2024 that outline planning permissions are exempt from the BNG condition. 23. Through their submissions, the appellant highlights the BNG exemption for developments that do not impact a priority habitat and that affect less than 25m2 of onsite habitat with a biodiversity value greater than zero. The development would not affect a priority habitat but the back garden to the bungalow contains a grassed area as well as trees and other foliage. The layout details suggests that most of the vegetated garden and the trees would be impacted by the development.

12 Great Central Avenue , Ruislip, HA4 6UD — London Borough of Hillingdon — Appeal Decision Also, no information has been provided that clearly shows the garden area affected would be less than 25m2 or that it has no biodiversity value. As such, it would https://www.gov.uk/planning-inspectorate 4

12 Great Central Avenue , Ruislip, HA4 6UD — London Borough of Hillingdon — Appeal Decision Also, no information has been provided that clearly shows the garden area affected would be less than 25m2 or that it has no biodiversity value. As such, it would https://www.gov.uk/planning-inspectorate 4

12 Great Central Avenue , Ruislip, HA4 6UD — London Borough of Hillingdon — Appeal Decision Appeal Decision APP/R5510/W/25/3359178 seem that none of the BNG exemptions are applicable and so the proposal is subject to the mandatory requirement for 10% BNG. 24. Article 7(1A) of the Town and Country Planning (Development Management Procedure) Order 2015 (as amended) (DMP) sets out the minimum information that should accompany applications that are subject to the BNG requirement. No completed biodiversity metric calculation tool has been submitted that shows the pre-development biodiversity value of the onsite habitat. This should have been submitted under the terms of the DMP and not left to be dealt with by planning conditions. I find no sound reason why this information could not have been submitted. In the absence of this information, I cannot be satisfied the BNG requirement for the development would be fulfilled. 25. Furthermore, the proposal would require the removal of trees on the site and so its layout has not been designed to avoid the loss of existing vegetation. The trees are not protected and the appellant claims they are not of high quality. Nonetheless, it seems likely they contribute to the site’s current biodiversity value.

12 Great Central Avenue , Ruislip, HA4 6UD — London Borough of Hillingdon — Appeal Decision Moreover, the development would cover a significant proportion of the plot and I am unconvinced the remaining open spaces would be appropriate for new tree planting given their limited size and proximity to the proposed buildings. There is no planning obligation before me that would require contributions to be made to off-site biodiversity enhancements in the event the development would reduce the biodiversity value of the site. 26. Therefore, I conclude the development would have an unacceptable effect on biodiversity, in particular through the loss of existing trees and foliage. I am unconvinced that appropriate new planting could be secured through the reserved matters process that would fully offset the harmful effects of the removal of existing vegetation. In these regards, the proposal would not accord with LonP policy G6, LP1 policies BE1 and EM7 and LP2 policies DMEI7, DMHB11 and DMHB14. Amongst other things, these resist development that erodes the biodiversity value of gardens. Also, they seek to ensure BNG through developments and the retention of existing trees and landscaping. Air quality. 27. The site is within the declared Hillingdon Air Quality Management Area (the AQMA).

12 Great Central Avenue , Ruislip, HA4 6UD — London Borough of Hillingdon — Appeal Decision LP2 policy DMEI14 states that as a minimum development should be air quality neutral and in these respects it is consistent with LonP policy SI1. Also, it requires development to actively contribute towards the improvement of air quality, especially within the AQMA. Although referred to, the submissions indicate the site is just outside the A40/South Ruislip Air Quality Focus Area. 28. LP1 policy EM8 states all major development within the AQMA should demonstrate air quality neutrality. The appeal proposal does not represent major development and so this requirement does not apply. At the same time, LP1 policy EM8 states that all development should not cause deterioration in local air quality levels. Moreover, paragraph 6.65 of LP2 states that planning applications for all relevant development should contain an assessment of the likely levels of air quality in the area. 29. No air quality assessment has been provided that sets out substantiated findings on the likely effects of the proposal on air quality. The appellant suggests it is unlikely the development would lead to a significant increase in vehicular https://www.gov.uk/planning-inspectorate 5

12 Great Central Avenue , Ruislip, HA4 6UD — London Borough of Hillingdon — Appeal Decision Appeal Decision APP/R5510/W/25/3359178 movements and that a planning condition on boiler emissions could be imposed. However, even if accepted, such factors fail to demonstrate an improvement to air quality within the AQMA would be achieved. In such circumstances, I cannot rule out the need for additional measures to address air quality issues beyond those that could be incorporated as part of the development. As such, I am unconvinced the imposition of planning conditions would fully address the potential air quality issues. The Council suggests a planning obligation would be required that secures a contribution towards off-site air quality mitigation and enhancement measures. No planning agreement or undertaking is before me that includes such a planning obligation. 30. For these reasons, I conclude the development would have an unacceptable effect on air quality and that insufficient information has been provided to show that any ill-effects in these regards would be appropriately mitigated. In these respects, the development would be contrary to LonP policy SI1, LP1 policy EM8 and LP2 policy DMEI14.

12 Great Central Avenue , Ruislip, HA4 6UD — London Borough of Hillingdon — Appeal Decision As there is no planning obligation to secure payment towards off-site air quality improvement measures, the development would also be contrary to LP2 policy DMCI7. The Council’s refusal reason also refers to LonP policy DF1 but this contains no provisions that are relevant to this matter. Effect on living conditions at No 14. 31. No detailed assessment has been carried out that convincingly demonstrates the effects of the development on access to light at No 14. Even so, I envisage the proposed house would cause additional overshadowing onto No 14 due to its height and position near to the common boundary. 32. The most immediate loss of light would be to a car parking area and a driveway rather than to any windows within No 14. Also, the house would be set away from No 14’s rear elevation and it would be positioned towards the side rather than directly behind the property. As such, it would have no significant effect on light reaching No 14’s rear windows during large parts of the day. Furthermore, the development would not lead to a sense of enclosure to the rear of No 14 so as to result in a unacceptable outlook. 33.

12 Great Central Avenue , Ruislip, HA4 6UD — London Borough of Hillingdon — Appeal Decision Consequently, I conclude the development would have an acceptable effect on living conditions at No 14. In these regards, it would accord with LonP policy D6 and LP2 policy DMHB11. Amongst other things, these seek to ensure development provides sufficient daylight and sunlight to surrounding housing. Other Matters and Planning Balance 34. The site is within a settlement and is suitable in general terms for residential development. As such, the proposal is supported by the provisions of the Framework at paragraph 124. Residents of the development would have good access to local services and public transport links to the wider area. As a small scheme the proposal could be constructed fairly quickly and it would make a modest contribution to the supply of new housing. These factors all add weight towards allowing the appeal. 35. However, the proposal would be contrary to several development plan policies. The harm as a result of these policy conflicts significantly and demonstrably outweighs the benefits of the scheme. Therefore, even if paragraph 11(d) of the Framework is engaged due to an insufficient supply of housing land, the https://www.gov.uk/planning-inspectorate 6

12 Great Central Avenue , Ruislip, HA4 6UD — London Borough of Hillingdon — Appeal Decision Appeal Decision APP/R5510/W/25/3359178 circumstances at sub-paragraph 11(d)(ii) apply. As such, the proposal does not benefit from the presumption in favour of sustainable development as set out under paragraph 11 of the Framework. Accordingly, I find insufficient justification to allow the appeal contrary to development plan policies. Conclusion 36. For the above reasons, I conclude the appeal should be dismissed.

12 Great Central Avenue , Ruislip, HA4 6UD — London Borough of Hillingdon — Jonathan Edwards INSPECTOR https://www.gov.uk/planning-inspectorate 7