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
87% 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
-
26/06295/FULL Awaiting decision
15 Warwick Way London SW1V 1QT
Installation of a new shopfront with Medication Dispensing Outlet.
-
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.
-
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.
-
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)
-
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)