Planning application
26/01860/FULL
Flat 4b Block 4 Portman Mansions Chiltern Street London W1U 6NS
Proposal
Like for like replacement of nine windows at lower ground floor level.
As published by the council, reference 26/01860/FULL
Timeline
Dates from the published record
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23 Mar 2026
Received by Westminster
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7 Apr 2026
Validated
Checked as complete and ready for consideration.
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21 Jul 2026
Added to PlanIndex
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Decision
Awaiting decision
The statutory target is eight weeks for most applications and thirteen for major development. Extensions of time are common.
What happens while it is decided
The process from here
This application is with Westminster for determination. The council publicises it, consults neighbours and technical bodies where required, and weighs the responses against local and national planning policy.
The statutory target is eight weeks for most applications and thirteen for major development, though extensions of time are common. Comments carry most weight while the case is undecided, so check the council portal for the deadline if you want to respond.
About full applications applications
How this application type works
A full application seeks permission for a complete, detailed proposal in one go: siting, design, access and landscaping are all fixed at this stage. It is the standard route for new buildings, conversions and changes of use. The statutory target is eight weeks for smaller schemes and thirteen weeks for major development, though complex cases often take longer by agreement.
Nearby applications
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25/06866/TCA Withdrawn
Flat 4a Block 4 Portman Mansions Chiltern Street London W1U 6NS
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25/05866/FULL Refused
Flat 1D Block 1 Portman Mansions Chiltern Street London W1U 5AJ
Replacement of existing single-glazed timber sash and casement windows with double-glazed timber sash and casement windows to match the existing style and opening type. Existing window frames to be retained with no changes to the structural openings.
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26/04634/NMA Awaiting decision
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26/02263/ADV Awaiting decision
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Display of externally illuminated projecting sign measuring 0.9m X 1.2m, externally illuminated fascia sign measuring 6.203m X 0.705m, 2.563m X 0.3m, 1.25m X 0.9m, non illuminated fascia sign measuring 1.2m X 0.2m, 0.25m X 0.25m,0.47m X 0.9m, internally illuminated other sign measuring 1.88m X 0.6m, 1.415m X 0.6m, internally illuminated fascia sign measuring 0.377m X 0.5m and non illuminated other sign 0.261m X 0.187m
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03/04543/FULL Granted
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Installation of boiler flue, ventilation extract and replacement of rear window at first floor level.
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03/04432/LBC Decided
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Alterations including division of window to balcony at rear, installation of gas and electric meters and boiler flue extractor fan outlets on balcony, modifications to internal layout and new front door.
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26/04989/FULL Awaiting decision
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26/04986/FULL Awaiting decision
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