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Planning application

12 Chester Street London SW1X 7BB

Awaiting decision Westminster 26/01507/FULL Full Planning Permission Application

Works: Extension Loft or dormer Windows or glazing

Still open. Anyone can comment while the consultation period runs, and comments go to the council rather than to us.

Proposal

Variation of condition 1 of planning permission dated 24th July 2025 (RN 24/05883/FULL) for the Excavation of a new basement level. Replacement of existing rear extension at first, second and third with a new rear extension (first to third floor level) with flat roof. Erection of an extension at rear ground floor level. Removal of the existing kitchen rooflight and extension of existing terrace at first floor level. Replacement of existing windows and French doors with new. NAMELY, to omit the approved basement and minor amendments to the upper floors.

As published by the council, reference 26/01507/FULL

Application record

Reference
26/01507/FULL
Type
Full Planning Permission Application
Status
Pending
Received
9 Mar 2026
Validated
9 Mar 2026
Ward
Knightsbridge & Belgravia
Postcode
SW1X 7BB

Site history

Applications at this address on the Westminster register

This site has had 5 applications since 2025: 3 approved, 0 refused.

  • 26/02886/LBC Awaiting decision

    12 Chester Street London SW1X 7BB

    Replacement of existing rear extension at first, second and third with a new rear extension (first to third floor level) with flat roof. Erection of an extension at rear ground floor level. Removal of the existing kitchen rooflight and extension of existing terrace at first floor level. Replacement of existing windows and French doors with new; and alterations to French door width at rear first floor level.

    Submitted 1 May 2026 Heritage and listed buildings
  • 26/00535/NMA Granted

    12 Chester Street London SW1X 7BB

    Amendment to planning permission dated 24th July 2025 (RN 24/05883/FULL) for the Excavation of a new basement level. Replacement of existing rear extension at first, second and third with a new rear extension (first to third floor level) with flat roof. Erection of an extension at rear ground floor level. Removal of the existing kitchen rooflight and extension of existing terrace at first floor level. Replacement of existing windows and French doors with new; NAMELY to amend the description of development to omit 'Excavation of a new basement level'; amended description of development to read as follows: 'Replacement of existing rear extension at first, second and third with a new rear extension (first to third floor level) with flat roof. Erection of an extension at rear ground floor level. Removal of the existing kitchen rooflight and extension of existing terrace at first floor level. Replacement of existing windows and French doors with new'.

    Decided 16 Mar 2026 Amendments
  • 25/09271/FULL Granted

    12 Chester Street London SW1X 7BB

    Installation of air conditioning units within an acoustic enclosure at roof level and replacement of the existing lead flat roof with a new lead flat roof.

    Decided 8 May 2026 Full applications
  • 25/09272/LBC Granted

    12 Chester Street London SW1X 7BB

    Installation of air conditioning units within an acoustic enclosure at roof level and replacement of the existing lead flat roof with a new lead flat roof.

    Decided 8 May 2026 Heritage and listed buildings

Timeline

Dates from the published record

  1. 9 Mar 2026

    Received by Westminster

  2. 21 Jul 2026

    Added to PlanIndex

  3. Decision

    Awaiting decision

    Decision expected by 4 May 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 91 days over the applications it decided in the last year.

Documents

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

17 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.

Watch members (£5 a month) open the document list from here.

Open the documents

What 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 full applications in a median of 119 days. More in our guide to how long planning decisions take.

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

  • 12 Chester Street London SW1X 7BB

    26/02886/LBC Submitted 1 May 2026 50 yards away

    90% historically approved · decision due ~26 Jun

    Replacement of existing rear extension at first, second and third with a new rear extension (first to third floor level) with flat roof. Erection of an extension at rear ground floor level. Removal of the existing kitchen rooflight and extension of existing terrace at first floor level. Replacement of existing windows and French doors with new; and alterations to French door width at rear first floor level.

    Awaiting decision Heritage and listed buildings Extension Loft or dormer +1 12 docs
  • 12 Chester Street London SW1X 7BB

    25/09272/LBC Submitted 22 Dec 2025 50 yards away

    Installation of air conditioning units within an acoustic enclosure at roof level and replacement of the existing lead flat roof with a new lead flat roof.

    Granted Heritage and listed buildings 17 docs
  • 12 Chester Street London SW1X 7BB

    26/00535/NMA Submitted 29 Jan 2026 50 yards away

    Amendment to planning permission dated 24th July 2025 (RN 24/05883/FULL) for the Excavation of a new basement level. Replacement of existing rear extension at first, second and third with a new rear extension (first to third floor level) with flat roof. Erection of an extension at rear ground floor level. Removal of the existing kitchen rooflight and extension of existing terrace at first floor level. Replacement of existing windows and French doors with new; NAMELY to amend the description of development to omit 'Excavation of a new basement level'; amended description of development to read as follows: 'Replacement of existing rear extension at first, second and third with a new rear extension (first to third floor level) with flat roof. Erection of an extension at rear ground floor level. Removal of the existing kitchen rooflight and extension of existing terrace at first floor level. Replacement of existing windows and French doors with new'.

    Granted Amendments Extension Loft or dormer +1 8 docs
  • 12 Chester Street London SW1X 7BB

    25/09271/FULL Submitted 22 Dec 2025 50 yards away

    Installation of air conditioning units within an acoustic enclosure at roof level and replacement of the existing lead flat roof with a new lead flat roof.

    Granted Full applications 22 docs
  • 4 Chester Street London SW1X 7BB

    20/06906/FULL Submitted 30 Oct 2020 50 yards away

    Variation of Condition 1 of planning permission dated 31 Janurary 2017 (RN: 16/11228/FULL) for the: Construction of a full width extension at rear lower ground and half width extension at upper ground floor level ; replacement of timber steps to front lightwell with metal steps, new door to front lightwell and lowering part of the vaults floor; replacement of existing rooflight with larger frameless double-glazed rooflight and one new rooflight at main roof level; replacement of doors at rear upper ground floor with a new window; and external renovation and repair works. Namely, to allow the removal of low wall to the rear terrace at first-floor level and replace with black painted railings.

    Granted Full applications Extension Loft or dormer +1 13 docs
  • 24 Chester Street London SW1X 7BL

    26/00077/FULL Submitted 7 Jan 2026 50 yards away

    Erection of two storey rear extension at ground and lower ground floor level and associated works.

    Granted Full applications Extension 41 docs

In Westminster

  • 26/07528/FULL Awaiting decision

    69 Eaton Place London SW1X 8DF

    Installation of new cast iron water pipe on rear courtyard elevation. (Linked with 26/07529/LBC)

    Received 5 Nov, published by the council 6 Nov 2026 Full applications
  • 26/05200/FULL Decided

    1 The Court House 165 Seymour Place London W1H 4PU

    Installation of waterproofing system to the existing lead flat roofs

    Received 3 Aug, published by the council 28 Aug 2026 Full applications
  • 26/07521/FULL Awaiting decision

    Flat 18 Harlequin Court 20 Tavistock Street London WC2E 7NZ

    Installation of one external condenser unit

    Received 4 Nov, published by the council 6 Nov 2026 Full applications
  • 26/07508/FULL Awaiting decision

    Buckingham Palace The Mall London SW1A 1AA

    Replacement of existing security lighting to the Buckingham Palace Forecourt with 80 compact LED spotlights installed within the lantern clusters across 10 principal piers, with associated concealed cabling and reversible fixings. (Linked with 26/07509/LBC)

    Received 4 Nov, published by the council 5 Nov 2026 Full applications
  • 26/07472/FULL Awaiting decision

    Flat 3 82 New Cavendish Street London W1G 9TA

    Replacement windows to second floor level with vacuum, double glazing windows. (Linked with 26/07473/LBC)

    Received 3 Nov, published by the council 6 Nov 2026 Full applications