Replacement of the existing rear double-height conservatory with a brick-built predominantly glazed rear addition

Appeal Decision Site visit made on 15 September 2026 by Ellie Nutman BA (Hons) Decision by John Morrison BA (Hons) MSc MRTPI an Inspector appointed by the Secretary of State Decision date: 29th September 2026 Appeal Ref: 6012425 21 Belgrave Gardens, London NW8 0QY • 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 Andrew Galen against the decision of City of Westminster Council. • The application Ref is 26/03027/FULL. • The development proposed is replacement of the existing rear double-height conservatory with a brick-built predominantly glazed rear addition. Decision 1. The appeal is allowed and planning permission is granted for replacement of the existing rear double-height conservatory with a brick-built predominantly glazed rear addition, at 21 Belgrave Gardens, London NW8 0QY in accordance with the terms of the application, Ref 26/03027/FULL, subject to the following conditions: 1) The development hereby permitted shall begin not later than 3 years from the date of this decision. 2) The development hereby permitted shall be carried out in accordance with the following approved plans: ‘Location Plan’, am254-DFP-AR-061-204-R00 ‘Plans - Proposed’, am254-DEL-AR-062-204-R00 ‘Front & Rear Elevations – Proposed’, am254-DSC-AR-063-201-R00 ‘Section A - Existing & Proposed’, am254-DSC-AR-063-204-R00 ‘Section B - Existing & Proposed’. 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. A Revised National Planning Policy Framework (the Framework) was published on 17 August 2026. There have been some layout and subsequent paragraph numbering changes, as well as minor relevant alterations to the ways in which heritage matters are considered. I am however satisfied that, having reviewed the relevant changes, they do not have a material bearing on the substance of the main issue or indeed the arguments of the main parties thereon. Since they would not therefore be prejudiced, I have proceeded without further consultation. Main Issue 4. The main issue is whether the proposed development would preserve or enhance the character or appearance of the St John’s Wood Conservation Area (CA). Appeal Decision 6012425 2 Reasons for the Recommendation 5. The significance of the CA derives in part from its leafy, residential character, and was originally envisaged as an Arcadian Suburb. Terraces are generally tightly planned on modest plots. The appeal building sits within such a terrace and the appeal proposal would replace the existing two storey conservatory structure, infilling the space between the outrigger and neighbouring wall. The gardens and spaces to the rear of these terraces are close-knit and the existing structure appears to be the only of its kind within this row. The rear elevation and garden area are not readily visible from the public street scene. 6. The proposed extension would be in the same position, retain the same general form and scale, and serve the same function as the existing two-storey conservatory. Whilst the proposal would introduce a more contemporary design approach, the existing conservatory is itself a later addition rather than an original component of the host building. In effect, the development would replace one non- original rear extension with another of comparable size and siting. 7. I have been provided with no compelling evidence to demonstrate why a contemporary design response would be inappropriate in this location. The significance and character of the terrace row would be unaffected from the street scene. The appeal proposal would be confined to the rear and would replace an existing structure. Although the Council emphasises that the existing conservatory is a lightweight and subordinate addition, I note that the appeal proposal would retain the same overall scale and flat-roofed form whilst incorporating substantial areas of glazing. As such, I do not consider that the replacement of the existing structure would result in any increase in visual prominence. 8. Furthermore, the existing two-storey conservatory already appears to be a unique feature within this terrace row. Its presence indicates that the structure is not a characteristic or historically significant element of the terrace group that materially contributes to the significance of the conservation area. In these circumstances, I find that the replacement extension would preserve the character and appearance of the conservation area. Accordingly, the proposal would accord with Policies 42, 44 and 45 of the City Plan (2026) which require development to have regard to the character and appearance of the existing area, adjacent buildings and to ensure heritage assets and their settings are conserved and enhanced, in a manner appropriate to their significance. Conditions 9. In addition to the standard time limit condition, it is necessary to require the development to be carried out in accordance with the approved plans in the interests of certainty and enforcement. 10. The Council refers to Policy 40 of the City Plan (2026), which seeks to promote zero-carbon development and reduce energy demand. The proposal incorporates high-performance double glazing. Whilst the Council indicates that a condition requiring a green roof would have been imposed had planning permission been granted, Policy 40 contains no specific requirement for such. There is nothing to suggest to me that the use of the glazing specified would not meet the aspirational aims of this policy. I have not, therefore, recommended a condition requiring a green roof. Appeal Decision 6012425 3 Conclusion and Recommendation 11. For the reasons given above, the proposal would accord with the development plan. I therefore recommend it be allowed. Ellie Nutman APPEAL PLANNING OFFICER Inspector’s Decision 12. I have considered all the submitted evidence and my representative’s report and on that basis the appeal is allowed. Planning permission is therefore granted, subject to the conditions set out above. John Morrison INSPECTOR