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Planning application

21 Montagu Mews South London W1H 7ES

Awaiting decision Westminster 25/09359/FULL Full Planning Permission Application

Works: Extension Loft or dormer Roofing Windows or glazing

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

Proposal

Infill of existing light well to first floor at the rear, roof alterations including new conservation style roof lights and photovoltaic panels to the rear slope of the roof. Alterations to the front façade including the installation of new double doors with window over and removal metal bar to ground floor windows and installation of double glazed vacuum glazed double glazing within existing window units.

As published by the council, reference 25/09359/FULL

Application record

Reference
25/09359/FULL
Type
Full Planning Permission Application
Status
Pending
Received
24 Dec 2025
Validated
26 Mar 2026
Ward
Marylebone
Postcode
W1H 7ES

Timeline

Dates from the published record

  1. 24 Dec 2025

    Received by Westminster

  2. 26 Mar 2026

    Validated

    Checked as complete and ready for consideration.

  3. 20 Jul 2026

    Added to PlanIndex

  4. Decision

    Awaiting decision

    Decision expected by 21 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.

Who's behind it

Company information only, from the register and Companies House

Robin Ashley Architects LLP Agent, an architecture practice registered in Sheffield

Active · incorporated 2004 · Sheffield

14 applications on PlanIndex · across 10 councils · 75% granted

Trade members see everything this firm has filed, how it was decided, and get an email the day it files again.

See their track record

Documents

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

34 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.

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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.

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