17 William Mews London SW1X 9HF

This site has had 3 applications since 2026.

• 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.

  Submitted 3 Jul 2026 Full applications
• 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

1. 7 Apr 2026

   Received by Westminster

2. 21 Jul 2026

   Added to PlanIndex

3. Decision

   Awaiting decision

   Decision expected by 2 June 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.

This application is with Westminster for determination, against a statutory target of eight weeks. Over the last year Westminster decided full applications in a median of 91 days. More in our guide to how long planning decisions take.

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.

• 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

  26/04409/FULL Submitted 3 Jul 2026 50 yards away

  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 docs
  Domestic

• 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

• 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