15 Upper Wimpole Street , London , W1G 6LR

15 Upper Wimpole Street , London , W1G 6LR — City of Westminster Council — by Paul Martinson BA (Hons) MSc MRTPI an Inspector appointed by the Secretary of State Decision date: Tuesday 12 May 2026

15 Upper Wimpole Street , London , W1G 6LR — City of Westminster Council — 15 Upper Wimpole Street, London W1G 6LR • The appeal is made under section 78 of the Town and Country Planning Act 1990 (as amended) against a refusal to grant planning permission under section 73 of the Town and Country Planning Act 1990 (as amended) for the development of land without complying with conditions subject to which a previous planning permission was granted. • The appeal is made by 15UWS Design and Build Limited against the decision of City of Westminster Council. • The application Ref is 25/05015/FULL.

15 Upper Wimpole Street , London , W1G 6LR — City of Westminster Council — 15 Upper Wimpole Street, London W1G 6LR • The appeal is made under section 78 of the Town and Country Planning Act 1990 (as amended) against a refusal to grant planning permission under section 73 of the Town and Country Planning Act 1990 (as amended) for the development of land without complying with conditions subject to which a previous planning permission was granted. • The appeal is made by 15UWS Design and Build Limited against the decision of City of Westminster Council. • The application Ref is 25/05015/FULL.

15 Upper Wimpole Street , London , W1G 6LR — City of Westminster Council — 15 Upper Wimpole Street, London W1G 6LR • The application sought planning permission for ‘Variation of condition 1 of planning permission dated 3rd June 2025 (RN:25/00868/FULL) which itself varied condition 1 of planning permission dated 17 September 2024 (RN:23/07898/FULL) for Infilling of courtyard between the main house and mews house at basement level, installation of glazed sloping roof at rear ground floor level, excavation beneath basement to provide swimming pool, creation of terrace at rear ground floor level, creation of new door to facilitate access to terrace at rear first floor level, installation of plant equipment in roof space and at basement level and associated internal and external alterations, all in connection with existing dwelling house (Site includes 2 Dunstable Mews). Namely, internal and external alterations including the addition of a glazed openable roof over the central lightwell at ground floor level. (Application under Section 73 of the Act)’ without complying with a condition attached to planning permission Ref 25/00868/FULL, dated 3 June 2025.

15 Upper Wimpole Street , London , W1G 6LR — City of Westminster Council — 15 Upper Wimpole Street, London W1G 6LR • The condition in dispute is No 1 which states that: ‘The development hereby permitted shall be carried out in accordance with the drawings and other documents listed on this decision letter, and any drawings approved subsequently by the City Council as local planning authority pursuant to any conditions on this decision letter. 25/00868/FULL: A3100 Rev 00; A2100 Rev 01; A2110 Rev 02; A2120 Rev 03; A2130 Rev 02; A2140 Rev 02; A2200 Rev 03; A2210 Rev 02; A2310 Rev 042; A2350 Rev 01; A2300 Rev 04; A2160 Rev 04; A2150 Rev 04; D1100; D1110; D1120; D1130; D1140; D1150; D1160; Desk Study, Ground Investigation & Ground Movement Assessment, dated January 2025, ref J25009; Structural Methodology Statement - Addendum 30954-PAM-RP-S-0002 Rev P02. 23/07898/FULL: Demolition: 6368-0214 Rev PL02; 6368-0215 Rev PL02; 6368-0216 Rev PL02; 6368-0217 Rev PL02; 6368-0218 Rev PL02; 6368-0219 Rev PL02; 6368-0220 Rev PL02; 6368-0221 Rev PL02; 6368-0222 Rev PL01; 6368-0223 Rev PL02; 6368-0224 Rev PL01; 6368- 0225 Rev PL02; 6368-0226 Rev PL02.

15 Upper Wimpole Street , London , W1G 6LR — City of Westminster Council — 15 Upper Wimpole Street, London W1G 6LR Proposed: 6268-0228 Rev.PL02; 6268-0229 Rev.PL02; 6368-0230 Rev.PL03; 6268-0231 Rev.PL02; 6268-0232 Rev.PL02; 6268-0233 Rev.PL02; 6268- 0234 Rev.PL02; 6268-0235 Rev.PL02; 6368-0236 Rev.PL02; 6368-0237 Rev.PL03; 6368-0238 Rev.PL02; 6368-239 Rev.PL02; 6368-0240 Rev.PL02; 6368-0242 Rev.PL02; 6368-0243 Rev.PL01; 6368-0246 Rev.PL02; 6368-0247 (PL02); 6368-0248 (PL02); 6368-0249 (PL02); 6368-0250 (PL02); 6268-0230 Rev.PL03 Documents: Structural Methodology Statement, dated January 2024, reference 30954 1 (FOR INFORMATION ONLY) ; Flood Risk Assessment, revision 1, dated 17 October 2023 ; Acoustic Report reference 26611.PCR.01 Rev.B, dated 20 October 2023 ; Desk Study, Ground Investigation & Ground Movement Assessment, Dated October 2023, reference J23170 Rev 1; Odour Assessment, dated 13 November 2023, by Carnell Warren.’ • The reason given for the condition is: ‘For the avoidance of doubt and in the interests of proper planning.’

15 Upper Wimpole Street , London , W1G 6LR — City of Westminster Council — 15 Upper Wimpole Street, London W1G 6LS https://www.gov.uk/planning-inspectorate

15 Upper Wimpole Street , London , W1G 6LR — City of Westminster Council — 15 Upper Wimpole Street, London W1G 6LS https://www.gov.uk/planning-inspectorate Appeal Decisions APP/X5990/W/25/3374152, APP/X5990/Y/25/3374154 • The appeal is made under section 20 of the Planning (Listed Buildings and Conservation Areas) Act 1990 (as amended) against a refusal to grant listed building consent. • The appeal is made by 15 UWS Design and Build Limited against the decision of City of Westminster Council. • The application Ref is 25/05010/LBC. • The works proposed are Infilling of courtyard between the main house and mews house at basement and ground level, installation of glazed sloping roof at rear ground floor level, addition of a glazed openable roof over the central lightwell at ground floor level, excavation beneath basement to provide swimming pool, creation of terrace at rear ground floor level with area of planting, creation of new door to facilitate access to terrace at rear first floor level, installation of plant equipment in roof space and at basement level, alterations to the façade and associated internal and external alterations, all in connection with existing dwelling house. Decisions 1. Appeal A: The appeal is dismissed. 2. Appeal B: The appeal is dismissed. Preliminary Matters 3.

15 Upper Wimpole Street , London , W1G 6LR — City of Westminster Council — 15 Upper Wimpole Street, London W1G 6LS The appeal property forms part of a Grade II listed building referred to on the National Heritage List for England as ‘14-23, Upper Wimpole Street W1’. I have therefore had special regard to sections 16(2) and 66(1) of the Planning (Listed Buildings and Conservation Areas) Act 1990 (the Act). As the site also lies within the Harley Street Conservation Area (the CA), I have also had regard to Section 72(1) of the Act. 4. The two appeals concern the same scheme under different, complementary legislation. I have dealt with both appeals together in my reasoning. Background and Main Issues 5. Planning permission 23/07898/FULL granted planning permission for infilling of courtyard between the main house and mews house at basement level, installation of glazed sloping roof at rear ground floor level, excavation beneath basement to provide swimming pool, creation of terrace at rear ground floor level, creation of new door to facilitate access to terrace at rear first floor level, installation of plant equipment in roof space and at basement level and associated internal and external alterations, all in connection with existing dwelling house. 6.

15 Upper Wimpole Street , London , W1G 6LR — City of Westminster Council — 15 Upper Wimpole Street, London W1G 6LS This permission was varied by a subsequent grant of planning permission 25/00868/FULL following an application made under Section 73 of the Town and Country Planning Act 1990 (as amended) (S73). This varied condition 1 of 23/07898/FULL approving revised plans. This type of application is possible as a condition was imposed on the original permission, specifying the approved plans. 7. The application subject to Appeal A was also made under S73 and seeks a further revision to the plans approved by 23/07898/FULL and 25/00868/FULL to insert an openable glass roof above the existing lightwell. Appeal A seeks removal of that condition and replacement with a condition specifying the plans that reflect the amended proposal with the openable glass roof. 8. As set out above, the application subject to Appeal B was made under section 20 of the Act following the refusal of an application for listed building consent. This seeks listed building consent for an amended scheme to those that were earlier approved alongside the above grants of planning permission. The Council’s https://www.gov.uk/planning-inspectorate 2

15 Upper Wimpole Street , London , W1G 6LR — City of Westminster Council — 15 Upper Wimpole Street, London W1G 6LS Appeal Decisions APP/X5990/W/25/3374152, APP/X5990/Y/25/3374154 reasons for refusal identify harm from the proposed openable glass roof. This aspect of the proposal therefore forms the main part of my assessment below. 9. The main issues are therefore whether the proposed openable glass roof would preserve the Grade II listed building of 14-23, Upper Wimpole Street W1, and whether the proposal would preserve or enhance the character or appearance of the CA (Appeals A and B). Reasons Special Interest and Significance 10. 14-23 Upper Wimpole Street is a terrace of townhouses constructed between 1780 and 1790 as part of the Portland Estate developments overseen by John White, builder and surveyor. The individual properties are generally of four storeys over basements and constructed of brick with channelled or rusticated ground floors. The internal hierarchy of rooms is evident from the front elevation, with the elegant first floor windows being particularly tall and often featuring cast iron balconies.

15 Upper Wimpole Street , London , W1G 6LR — City of Westminster Council — 15 Upper Wimpole Street, London W1G 6LS There is a high degree of uniformity across the front facades and their Classical arrangement and symmetry, including in terms of the alignment of the fenestration, are elements which contribute to the listed building’s special interest and significance which are principally derived from its architectural and historic interest. 11. The rear elevations are more restrained, utilitarian and predominantly brick-faced. Whilst there is alignment to the rear fenestration, this is interrupted by the stairway windows being set down from each floor on half landings. Nonetheless this remains a broadly regular pattern and the hierarchy across the floors of the townhouses remains visible across the rear, with the tall first floor windows accentuating the vertical nature of this elevation. There is a similar regular pattern of ground floor closet wing extensions, some of which have been extended upwards, projecting out from the right side of the rear elevations leaving a lightwell or rear yard to the left. This consistent pattern is broken only at No 16, following approval in 2005, with lightwells persisting in some form alongside closet extensions at the majority of properties that make up the listed building. 12.

15 Upper Wimpole Street , London , W1G 6LR — City of Westminster Council — 15 Upper Wimpole Street, London W1G 6LS The surviving rear lightwells set alongside the closet wing extensions provide for an appreciation of the vertical nature of the townhouses and the full extent of their height above ground floor level. They also provide a degree of separation between the townhouses and the mews houses and hint at the gardens that once existed between them. On this basis, the lightwells to the rear of the townhouses within the listed terrace contribute to its special interest and significance. 13. The former gardens have now been predominantly infilled by development that began, at least, in the nineteenth century. Nonetheless the majority of the infill development is subservient to the mews houses and this historic relationship and evident hierarchy between the main dwellings and their associated mews is still readable and contributes to the special interest and significance of the listed buildings. 14. The appeal property, No 15, has an existing rear lightwell set alongside the closet wing extension which links to a hipped roof structure that adjoins 2 Dunstable Mews. This mews house forms part of the appeal property.

15 Upper Wimpole Street , London , W1G 6LR — City of Westminster Council — 15 Upper Wimpole Street, London W1G 6LS For the reasons set out above, through its retained lightwell and adjacent closet wing extension, the https://www.gov.uk/planning-inspectorate 3

15 Upper Wimpole Street , London , W1G 6LR — City of Westminster Council — 15 Upper Wimpole Street, London W1G 6LS For the reasons set out above, through its retained lightwell and adjacent closet wing extension, the https://www.gov.uk/planning-inspectorate 3 Appeal Decisions APP/X5990/W/25/3374152, APP/X5990/Y/25/3374154 appeal property reinforces the special interest and significance of the listed terrace. 15. 2 Dunstable Mews is understood to have been rebuilt in the early twentieth century by former occupant, abdominal surgeon Leonard Arthur Bidwell, to a style which complements the other similar buildings on the narrow side street, incorporating salt-glazed bricks to the external elevations. The subservient form, reflective of that of the wider mews and the use of salt-glazed brick as an external facing material are elements that contribute to the special interest and significance of the listed building. 16. No 15 is also located within the boundaries of the CA, designated in 1968. The CA is characterised by its tight-knit network of terraced townhouses, with many dating to the Georgian period and typically set in a regular grid street layout. The area retains a residential character albeit with a strong influence from the medical uses that extend across Harley Street and the surrounding streets.

15 Upper Wimpole Street , London , W1G 6LR — City of Westminster Council — 15 Upper Wimpole Street, London W1G 6LS In this regard, the significance of the CA, insofar as it relates to these appeals, is derived from its illustration of the development of London in the Georgian period and the prevalence of polite architecture, comprising of predominantly handsome terraces. 17. The uniformity across individual Georgian terraces, their Classical arrangement and the discernible hierarchy across floors and between townhouses and associated mews houses provides a level of coherence within the CA that contributes positively to its character and appearance, and thus the significance of this area as a heritage asset. Forming part of a Classical Georgian terrace with a discernible vertical and lateral hierarchy as set out above, the appeal site thus contributes positively in those respects. Proposals and Effects 18. The proposed amendment to the previous approval would introduce a new glazed pyramidal roof to the lightwell, attaching to the boundary wall of the adjoining property, the approved parapet of the closet wing extension, and the salt-glazed brick elevation of the mews extension. It would also attach to the rear elevation of the listed building at a point just below the first floor windows. 19.

15 Upper Wimpole Street , London , W1G 6LR — City of Westminster Council — 15 Upper Wimpole Street, London W1G 6LS The provision of the roof at roughly first floor level would result in the loss of the lightwell disrupting the near continuous pattern of lightwells along the rear of the listed building. Its construction would merge the built form at ground floor level, eroding the legibility of the closet wing extension and main dwelling as distinct elements to the mews house, and preventing an appreciation of the full extent of the rear elevation, in views from within the dwelling, and from neighbouring properties within the terrace and beyond. As it would interrupt the space between the ground floor and first floor it would also erode the legibility of the vertical hierarchy of rooms on the rear elevation through limiting the ability to appreciate the ground floor and first floor elevations together. 20. I appreciate the structure is glazed and would potentially allow some views of the rear of the building when standing within it. Nonetheless, the provision of an intervening structure would ensure that there would be considerable interruption to those views from ground floor level looking up and from the upper rooms looking down.

15 Upper Wimpole Street , London , W1G 6LR — City of Westminster Council — 15 Upper Wimpole Street, London W1G 6LS Views of the full extent of the rear of the building would be even further limited from outside of No 15. https://www.gov.uk/planning-inspectorate 4

15 Upper Wimpole Street , London , W1G 6LR — City of Westminster Council — 15 Upper Wimpole Street, London W1G 6LS Views of the full extent of the rear of the building would be even further limited from outside of No 15. https://www.gov.uk/planning-inspectorate 4 Appeal Decisions APP/X5990/W/25/3374152, APP/X5990/Y/25/3374154 21. The harm identified would be evident from neighbouring properties as well as from the appeal site. The building over of the lightwell and the disruption to the regular pattern of lightwells and legibility of the vertical and lateral hierarchy within the terrace would, for the reasons set out above, incrementally erode the character of the CA. Whilst the magnitude of this harm would be modest, in the context of the CA as a whole, it would nevertheless fail to preserve or enhance its identified character and appearance. 22. For the above reasons, the proposal would fail to preserve the Grade II listed building, 14-23, Upper Wimpole Street W1, or any features of special architectural or historic interest which it possesses. It would also fail to preserve the character and appearance of the CA. This would be contrary to the requirements of sections 16(2), 66(1), and 72(1) of the Act. In doing so it would cause harm to the significance of these designated heritage assets. Heritage Balance 23.

15 Upper Wimpole Street , London , W1G 6LR — City of Westminster Council — 15 Upper Wimpole Street, London W1G 6LS When considering the impact of proposals on the significance of a designated heritage asset, the National Planning Policy Framework (the Framework) sets out that great weight should be given to the asset’s conservation. It makes clear that the more important the asset, the greater the weight should be. This is irrespective of whether any potential harm amounts to substantial harm, total loss or less than substantial harm to its significance. 24. Having regard to the extent and nature of the proposal, the harm to the special interest and significance of the listed building and the CA I have identified would amount to a moderate level of ‘less than substantial’ harm, as set out in the Framework. Paragraph 215 advises that this harm should be weighed against the public benefits of the proposal. 25. As set out above, the proposal is an amended scheme that generates a number of heritage benefits. These include the provision of replacement square mansard dormers, new paving in place of tarmac, restoration of mosaic and marble steps to entrance, rationalisation of downpipes on front elevation, and the restoration of the Georgian design front door fanlight.

15 Upper Wimpole Street , London , W1G 6LR — City of Westminster Council — 15 Upper Wimpole Street, London W1G 6LS These would represent aesthetic improvements to the listed building and thus would amount to public benefits that would carry moderate weight, albeit that these benefits would not be dependent upon the provision of a glazed roof to the lightwell. 26. Given that the proposal would result in the loss of outside space, I am not convinced that the provision of outside space in the form of the roof terrace would constitute a meaningful benefit. Moreover, any benefit in this regard would principally be for the occupants, rather than the wider public. This therefore carries limited weight. 27. The moderate public benefits, including heritage benefits, taken together, are not sufficient to outweigh the considerable importance and weight I attach to the identified harm to the significance of the designated heritage assets. 28. The proposed openable glass roof would fail to preserve the Grade II listed building of 14-23, Upper Wimpole Street W1 or any features of special architectural or historic interest which it possesses. In that regard, it would be harmful to its special interest. The proposal would also fail to preserve the https://www.gov.uk/planning-inspectorate 5

15 Upper Wimpole Street , London , W1G 6LR — City of Westminster Council — 15 Upper Wimpole Street, London W1G 6LS Appeal Decisions APP/X5990/W/25/3374152, APP/X5990/Y/25/3374154 character or appearance of the CA. This would be contrary to the requirements of sections 16(2), 66(1), and 72(1) of the Act. 29. The harmful impact would conflict with Policies 38, 39 and 40 of the Westminster City Plan (2021), which, amongst other things, together, seek to ensure new development represents high quality design that is appropriate to its context, including the historic environment, and preserves heritage assets. There would also be conflict with the provisions within the Framework which seek to conserve and enhance heritage assets. 30. Conflict would also occur with the guidance contained within the City of Westminster Repairs and Alterations to Listed Buildings Supplementary Planning Guidance (1996) which, amongst other things, guides that the integrity of historic buildings can easily be undermined by piecemeal alteration and that extensions that would detract from the uniformity of a formal group of buildings, or from the integrity of a particular design would likely be unacceptable. Other Matters 31.

15 Upper Wimpole Street , London , W1G 6LR — City of Westminster Council — 15 Upper Wimpole Street, London W1G 6LS The agent has stated that the installation of the glazed roof is wholly reversible, however, it would still require a substantial supporting framework to the adjacent walls, including historic fabric which would likely require repair. Moreover, nothing I have seen would indicate that there is a realistic possibility that future occupiers would seek to remove the structure. I have therefore attributed limited weight to this matter. 32. The appellant has drawn my attention to historic planning and listed building consent approvals of infilling of lightwells with new development away from the listed terrace, in other positions along Upper Wimpole Street at No 12 and No 24. These are listed separately to the appeal property. I am nonetheless not provided with full details of the circumstances under which these were approved including in terms of their special interest and with regard to public benefits. I would also note that evidence of existing harm to other listed buildings is not justification for further harm to another, separate, listed building. These historic approvals therefore carry limited weight in terms of my assessment. Conclusion 33. Appeal A: The proposal would conflict with the development plan.

15 Upper Wimpole Street , London , W1G 6LR — City of Westminster Council — 15 Upper Wimpole Street, London W1G 6LS There are no material considerations that indicate that the decision should be made other than in accordance with the development plan. Therefore, for the reasons given, I conclude that Appeal A should be dismissed. 34. Appeal B: For the above reasons and having regard to all matters raised I conclude that Appeal B should be dismissed.

15 Upper Wimpole Street , London , W1G 6LR — City of Westminster Council — Paul Martinson INSPECTOR https://www.gov.uk/planning-inspectorate 6