Planning application
17 William Mews London SW1X 9HF
Works: Extension Windows or glazing Domestic
Read from the description, not a valuation. How we read the register
Still open. Anyone can comment while the consultation period runs, and comments go to the council rather than to us.
Proposal
Amendments to planning permission dated 12 June 2025 (RN: 24/07507/FULL) for the erection of a roof extension and alterations to existing front elevation and fenestration. Excavation of a new basement below part existing dwellinghouse.; NAMELY minor amendments to the ground floor front elevation including revisions to the approved window openings, together with associated minor internal reconfiguration works.
As published by the council, reference 26/02952/NMA
Application record
- Reference
- 26/02952/NMA
- Type
- Non-material amendments
- Status
- Pending
- Received
- 5 May 2026
- Validated
- 12 May 2026
- Ward
- Knightsbridge & Belgravia
- Postcode
- SW1X 9HF
Site history
Applications at this address on the Westminster register
This site has had 3 applications since 2026.
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26/04409/FULL Decided
17 William Mews London SW1X 9HF
Variation of Condition 1 of planning permission dated 12 June 2025 (RN: 24/07507/FULL) for the erection of a roof extension and alterations to existing front elevation and fenestration; excavation of a new basement below part existing dwellinghouse; Namely, amendments to the ground floor windows.
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26/02286/ADFULL Awaiting decision
17 William Mews London SW1X 9HF
Details of all flood resilient and resistant measures (including finished floor levels) pursuant to condition 4 of planning permission dated 17th June 2025 (RN: 24/07507/FULL).
Timeline
Dates from the published record
-
5 May 2026
Received by Westminster
-
12 May 2026
Validated
Checked as complete and ready for consideration.
-
21 Jul 2026
Added to PlanIndex
-
Decision
Awaiting decision
Decision expected by 7 July 2026, 8 weeks from validation under the statutory target for most applications. Extensions of time are common and are agreed case by case.
Westminster took a median of 66 days over the applications it decided in the last year.
Who's behind it
Company information only, from the register and Companies House
Savills Limited Agent, registered in London
Active · incorporated 1987 · London
2,189 applications on PlanIndex · across 186 councils · 92% granted
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See their track recordDocuments
Plans, drawings, consultee responses and the officer's report
12 documents on file for this application
A planning file usually holds the application form, drawings and site plans, consultee responses, the officer's report and the decision notice.
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Open the documentsWhat happens while it is decided
This application is with Westminster for determination, against a statutory target of eight weeks. Over the last year Westminster decided amendment applications in a median of 54 days. More in our guide to how long planning decisions take.
About amendment applications
An amendment application makes limited changes to a permission that already exists; anything beyond modest adjustment needs a fresh application. More in our guide to planning application types.
Nearby applications
Within 0.3 miles
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17 William Mews London SW1X 9HF
87% historically approved · decision due ~2 Jun
Details of all flood resilient and resistant measures (including finished floor levels) pursuant to condition 4 of planning permission dated 17th June 2025 (RN: 24/07507/FULL).
Awaiting decision Full applications 5 docs -
17 William Mews London SW1X 9HF
87% historically approved · decision due ~1 Sep
Variation of Condition 1 of planning permission dated 12 June 2025 (RN: 24/07507/FULL) for the erection of a roof extension and alterations to existing front elevation and fenestration; excavation of a new basement below part existing dwellinghouse; Namely, amendments to the ground floor windows.
Decided Full applications Extension Windows or glazing 16 docsDomestic -
11 Lowndes Square London SW1X 9HB
89% historically approved · decision due ~23 Jun
External repairs and redecoration to the front and rear elevations; and other associated works at 11-12 Lowndes Square.
Awaiting decision 5 docs -
43 William Mews London SW1X 9HQ
Erection of an infill extension at ground and first floor rear replacing the existing first floor enclosed balcony and the ground floor undercroft; installation of new rooflight on main roof.
Granted Full applications Extension Loft or dormer 13 docs -
25 Kinnerton Street London SW1X 8EA
87% historically approved · decision due ~30 Jun
Extensions at rear, roof and basement levels to create 2 x 5 bedroom dwellings at 25 and 27 Kinnerton Street; new rear balconies at second floor level, PV panels, green roofs and associated works. (SITE 25 & 27 Kinnerton Street)
Awaiting decision Full applications Extension 58 docs -
23 Lowndes Square London SW1X 9HD
Installation of automatic security gate to an existing opening on front elevation of block No. 25 (site includes 23-25 Lowndes Square).
Granted Full applications 5 docs
Other amendment applications
In Westminster
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26/06232/NMA Awaiting decision
37 Trevor Place London SW7 1LE
Amendments to planning permission dated 17th July 2026 (RN 26/03030/FULL) for the Alterations including enlargement of louvres and installation of new plant in basement; landscaping of roof terrace; second floor windows replaced with door sets; partial demolition at ground and first floor levels to create new lightwell and landscaped courtyard. NAMELY, addition of a free-standing sauna to the second-floor roof terrace.
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26/06256/NMA Awaiting decision
Queens Court Queensway London W2 4QN
Amendments to planning permission dated 21st May 2026 (RN:25/05013/FULL) for Variation of conditions 1, 3, 8, 9 and 17 of planning permission dated 11th May 2022 (RN 18/09765/FULL) for the Change of use of rear part of Queensway Market to Retail, Financial and Professional services, Office and Restaurant (within Class E) use and 5 residential units facing Princes Court, reconfiguration of retail units along Queensway including introduction of Retail uses at Nos.23 and 33 (current entrances to Queensway Market) and use of Nos.25 and 41-43 Queensway as Restaurant uses, installation of new shopfronts to Nos.23 to 43 Queensway 23-43, erection of infill extension to rear at ground floor level, erection of two new pavilion structures for Retail use and associated new hard and soft landscaping on land between Queens Court and Princes Court, installation of green roofs, rooflights and mechanical plant within enclosures to first floor level roofs between projecting rear wings of Queens Court installation of kitchen extract ducts to rear elevations, and associated cycle parking, waste storage, plant and other ancillary alterations ('Application 2'). Namely, to vary the hours of operation for the refrigeration plant controlled by condition 6.
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26/06251/NMA Awaiting decision
19 Cumberland Street London SW1V 4LS
Amendments to planning permission dated 20th March 2026 (RN:25/08960/FULL) for Lower ground floor rear infill extension with terrace above, replacement of rear first floor conservatory, new roof level rear single dormer with access to third floor roof terrace, alterations to windows and external refurbishment, namely the change of conservatory gable roof to a flat GRP roof.
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26/06201/NMA Awaiting decision
Almack House 28 King Street St James's London SW1Y 6QW
Amendments to planning permission dated 16th April 2026 (RN:26/01487/FULL) for Installation of a mechanical plant at lower ground floor and installation of two grilles to two lower ground floor windows, namely change to approved grille.
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26/06212/NMA Awaiting decision
10 - 11 Lancaster Gate London W2 3LH
Amendment to Condition 12 (Whole Life Carbon) of planning permission dated 19th April 2024 (RN 23/04044/FULL) for Change of use from hotel to residential use (Class C3) with associated internal alterations to create 11 new units and external alterations comprising reconfiguration and recladding of the rear extension and restoration of the existing building. Namely to include additional requirement to evidence and justify where benchmarks cannot be achieved, consider mitigation measures and if none, evidence that all mitigation measures have been exhausted. (Linked with RN 26/06213/ADFULL)