Planning application
12 Chester Street London SW1X 7BB
Permission granted. Work must normally begin within three years of the decision or the permission lapses.
Proposal
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.
As published by the council, reference 25/09271/FULL
Application record
- Reference
- 25/09271/FULL
- Type
- Full Planning Permission Application
- Status
- Decided
- Decision
- Granted As published: Application Permitted
- Received
- 22 Dec 2025
- Validated
- 22 Dec 2025
- Decided
- 8 May 2026
- Ward
- Knightsbridge & Belgravia
- Decision by
- Delegated Decision
- 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.
-
26/01507/FULL Awaiting decision
12 Chester Street London SW1X 7BB
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.
-
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'.
-
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.
Timeline
Dates from the published record
-
22 Dec 2025
Received by Westminster
-
8 May 2026
Decision issued: Application Permitted
-
20 Jul 2026
Added to PlanIndex
Documents
Plans, drawings, consultee responses and the officer's report
22 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 documentsWhat this grant of permission means
Westminster granted permission on 8 May 2026, subject to any conditions on the decision notice. Work must normally begin within three years or the permission lapses. 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
-
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'.
Granted Amendments Extension Loft or dormer +1 8 docs -
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.
Granted Heritage and listed buildings 17 docs -
12 Chester Street London SW1X 7BB
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
88% historically approved · decision due ~4 May
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.
Awaiting decision Full applications Extension Loft or dormer +1 17 docs -
24 Chester Street London SW1X 7BL
Erection of two storey rear extension at ground and lower ground floor level and associated works.
Granted Full applications Extension 41 docs -
24 Chester Street London SW1X 7BL
Erection of two storey rear extension at ground and lower ground floor level and associated works.
Granted Heritage and listed buildings Extension 34 docs
Other full applications
In Westminster
-
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)
-
26/07460/FULL Awaiting decision
1 Hanover Square London W1S 1HA
Installation of new public art sculptures and seating; hard and soft landscaping; installation of an area of raised terrace decking on St George Street measuring 43m x 2.6m for the placing of tables, chairs and banquette benches in connection with restaurant use; and associated external alterations and enabling works.
-
26/07451/FULL Awaiting decision
Flat 1 31 South Audley Street London W1K 2PG
Replacement of windows, Installation of an external condenser to the rear elevation including Internal refurbishment. (linked with 26/07452/LBC)
-
26/07443/FULL Awaiting decision
150 Great Portland Street London W1W 6QD
Installation of three air conditioning condenser units to the lower ground floor rear courtyard, incluidng erection of a plunge pool. (retrospective)
-
26/06234/FULL Decided
40 Grosvenor Place London SW1X 7HJ
Use of lower ground floor of Unit 3 and ground floor of Unit 2 as gym (Class E(d)) and/ or office (Class E(g))