Planning application
56 Upper Montagu Street London W1H 1SN
Works: New dwelling Loft or dormer Roofing Windows or glazing
Relates to 25/09342/FULL
Still open. Anyone can comment while the consultation period runs, and comments go to the council rather than to us.
Proposal
Use of ground floor and mezzanine levels to rear as residential (Class C3) use; deconversion of ground floor and mezzanine levels to rear together with two studio flats and one one-bedroom flat to form one three-bedroom maisonette; creation of reconfigured office unit in basement; replacement of all but one window with slimline timber double glazed units installation of secondary glazing to one window; renovation of shopfront; reinstatement of glazed fanlight with opening vent, new solid panel door, and awning; new glazed doors to south elevation of mezzanine garden room; new metal balustrading across rear boundary and raised terrace surface level with walk-on roof lights; replacement of concrete roof tiles with slate and new glazed roof light/ roof access; creation of green roof above mezzanine garden room; removal of modern partition walls and reinstatement of historical plan form as far as possible; reinstatement of historic period features all in connection with the use of building as office at part basement level with the remainder of the building being used as a single residential unit (Class C3) and associated internal alterations. (Linked to 25/09342/FULL)
As published by the council, reference 25/09343/LBC
Application record
- Reference
- 25/09343/LBC
- Type
- Listed Building Consent Application
- Status
- Pending
- Received
- 24 Dec 2025
- Validated
- 24 Dec 2025
- Ward
- Marylebone
- Postcode
- W1H 1SN
Site history
Applications at this address on the Westminster register
This site has had 2 applications since 2025.
-
25/09342/FULL Awaiting decision
56 Upper Montagu Street London W1H 1SN
Use of ground floor and mezzanine levels to rear as residential (Class C3) use; deconversion of ground floor and mezzanine levels to rear together with two studio flats and one one-bedroom flat to form one three-bedroom maisonette; creation of reconfigured office unit in basement; replacement of all but one window with slimline timber double glazed units installation of secondary glazing to one window; renovation of shopfront; reinstatement of glazed fanlight with opening vent, new solid panel door, and awning; new glazed doors to south elevation of mezzanine garden room; new metal balustrading across rear boundary and raised terrace surface level with walk-on roof lights; replacement of concrete roof tiles with slate and new glazed roof light/ roof access; creation of green roof above mezzanine garden room; removal of modern partition walls and reinstatement of historical plan form as far as possible; reinstatement of historic period features all in connection with the use of building as office at part basement level with the remainder of the building being used as a single residential unit (Class C3) and associated internal alterations. (Linked to 25/09343/LBC)
Timeline
Dates from the published record
-
24 Dec 2025
Received by Westminster
-
20 Jul 2026
Added to PlanIndex
-
Decision
Awaiting decision
Decision expected by 18 February 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.
Related applications
Cases linked to this one on the register
-
25/09342/FULL Awaiting decision
56 Upper Montagu Street London W1H 1SN
Use of ground floor and mezzanine levels to rear as residential (Class C3) use; deconversion of ground floor and mezzanine levels to rear together with two studio flats and one one-bedroom flat to form one three-bedroom maisonette; creation of reconfigured office unit in basement; replacement of all but one window with slimline timber double glazed units installation of secondary glazing to one window; renovation of shopfront; reinstatement of glazed fanlight with opening vent, new solid panel door, and awning; new glazed doors to south elevation of mezzanine garden room; new metal balustrading across rear boundary and raised terrace surface level with walk-on roof lights; replacement of concrete roof tiles with slate and new glazed roof light/ roof access; creation of green roof above mezzanine garden room; removal of modern partition walls and reinstatement of historical plan form as far as possible; reinstatement of historic period features all in connection with the use of building as office at part basement level with the remainder of the building being used as a single residential unit (Class C3) and associated internal alterations. (Linked to 25/09343/LBC)
1 later application on the register refers to this one:
-
25/09342/FULL Awaiting decision
56 Upper Montagu Street London W1H 1SN
Use of ground floor and mezzanine levels to rear as residential (Class C3) use; deconversion of ground floor and mezzanine levels to rear together with two studio flats and one one-bedroom flat to form one three-bedroom maisonette; creation of reconfigured office unit in basement; replacement of all but one window with slimline timber double glazed units installation of secondary glazing to one window; renovation of shopfront; reinstatement of glazed fanlight with opening vent, new solid panel door, and awning; new glazed doors to south elevation of mezzanine garden room; new metal balustrading across rear boundary and raised terrace surface level with walk-on roof lights; replacement of concrete roof tiles with slate and new glazed roof light/ roof access; creation of green roof above mezzanine garden room; removal of modern partition walls and reinstatement of historical plan form as far as possible; reinstatement of historic period features all in connection with the use of building as office at part basement level with the remainder of the building being used as a single residential unit (Class C3) and associated internal alterations. (Linked to 25/09343/LBC)
Who's behind it
Company information only, from the register and Companies House
Stratagem Planning Consultants Ltd. Agent, a planning consultancy registered in London
Active · incorporated 2014 · London
7 applications on PlanIndex · across 4 councils
Trade members see everything this firm has filed, how it was decided, and get an email the day it files again.
See their track recordDocuments
Plans, drawings, consultee responses and the officer's report
21 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 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 heritage and listed building applications in a median of 119 days. More in our guide to how long planning decisions take.
About heritage and listed building applications
Listed building consent is needed for works that affect the special interest of a listed building, and carrying out such works without it is a criminal offence. More in our guide to planning application types.
Nearby applications
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56 Upper Montagu Street London W1H 1SN
88% historically approved · decision due ~18 Feb
Use of ground floor and mezzanine levels to rear as residential (Class C3) use; deconversion of ground floor and mezzanine levels to rear together with two studio flats and one one-bedroom flat to form one three-bedroom maisonette; creation of reconfigured office unit in basement; replacement of all but one window with slimline timber double glazed units installation of secondary glazing to one window; renovation of shopfront; reinstatement of glazed fanlight with opening vent, new solid panel door, and awning; new glazed doors to south elevation of mezzanine garden room; new metal balustrading across rear boundary and raised terrace surface level with walk-on roof lights; replacement of concrete roof tiles with slate and new glazed roof light/ roof access; creation of green roof above mezzanine garden room; removal of modern partition walls and reinstatement of historical plan form as far as possible; reinstatement of historic period features all in connection with the use of building as office at part basement level with the remainder of the building being used as a single residential unit (Class C3) and associated internal alterations. (Linked to 25/09343/LBC)
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