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Planning application

17 William Mews London SW1X 9HF

Decided Westminster 26/04409/FULL Full applications

Works: Extension Windows or glazing Domestic

Read from the description, not a valuation. How we read the register

Decided. The decision notice on the council portal carries the outcome in full, including any conditions.

Proposal

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.

As published by the council, reference 26/04409/FULL

Application record

Reference
26/04409/FULL
Category
Full applications
Status
Decided
Received
3 Jul 2026
Validated
7 Jul 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.

  • 26/02952/NMA Awaiting decision

    17 William Mews London SW1X 9HF

    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.

    Submitted 5 May 2026 Amendments
  • 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).

    Submitted 7 Apr 2026 Full applications

Timeline

Dates from the published record

  1. 3 Jul 2026

    Received by Westminster

  2. 7 Jul 2026

    Validated

    Checked as complete and ready for consideration.

  3. 21 Jul 2026

    Added to PlanIndex

  4. 18 Sep 2026

    Status changed to Decided

    Previously Pending.

Documents

Plans, drawings, consultee responses and the officer's report

16 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 documents

After the decision

Westminster has decided this application; the outcome above is the register's own wording and the decision notice on the council portal carries the detail. More in our guide to what happens after a planning decision.

About full applications

A full application seeks permission for a complete, detailed proposal in one go, with siting, design, access and landscaping all fixed at this stage. More in our guide to planning application types.

Nearby applications

Within 0.3 miles

  • 17 William Mews London SW1X 9HF

    26/02952/NMA Submitted 5 May 2026 50 yards away

    93% historically approved · decision due ~7 Jul

    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.

    Awaiting decision Amendments Extension Windows or glazing 12 docs
    Domestic
  • 17 William Mews London SW1X 9HF

    26/02286/ADFULL Submitted 7 Apr 2026 50 yards away

    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
  • 11 Lowndes Square London SW1X 9HB

    26/02696/CLLB Submitted 22 Apr 2026 50 yards away

    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

    25/09117/FULL Submitted 17 Dec 2025 50 yards away

    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

    26/02928/FULL Submitted 5 May 2026 50 yards away

    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

    04/05743/FULL Submitted 23 Jul 2004 100 yards away

    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

In Westminster

  • 26/06295/FULL Awaiting decision

    15 Warwick Way London SW1V 1QT

    Installation of a new shopfront with Medication Dispensing Outlet.

    Received 15 Sep, published by the council 17 Sep 2026 Full applications
  • 26/06297/FULL Awaiting decision

    15 Warwick Way London SW1V 1QT

    Alterations to rear elevation at basement level comprising replacement window and installation of double opening door.

    Received 15 Sep, published by the council 17 Sep 2026 Full applications
  • 26/06294/FULL Awaiting decision

    15 Eaton Mews South London SW1W 9HP

    Installation of railings and sliding lantern light at main roof level in connection with the use of the roof as a terrace.

    Received 15 Sep, published by the council 22 Sep 2026 Full applications
  • 26/06317/FULL Awaiting decision

    124 Hamilton Terrace London NW8 9UT

    Replacement of existing first-floor sash windows to the front and rear elevations with traditionally detailed painted timber, slim-profile double-glazed sash windows. (Linked to 26/06318/LBC)

    Received 15 Sep, published by the council 22 Sep 2026 Full applications
  • 26/06273/FULL Awaiting decision

    9A Grosvenor Square London W1K 5AE

    Installation of natural Portland Stone paving to two front entrances. (Linked to 26/05473/LBC)

    Received 14 Sep, published by the council 22 Sep 2026 Full applications