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Planning application

51 Upper Montagu Street London W1H 1FQ

Awaiting decision Westminster 26/00898/ADFULL Approval of Details (Full PP)

Works: Windows or glazing

Relates to 25/03874/FULL

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

Proposal

Details of supplementary acoustic report, detailed drawings of all new doors and windows, new first floor balconettes and investigative report of Phase 1 pursuant to condition 5, 7, 8 and 11 (part) of planning permission dated 24 October 2025 (RN: 25/03874/FULL).

As published by the council, reference 26/00898/ADFULL

Application record

Reference
26/00898/ADFULL
Type
Approval of Details (Full PP)
Status
Pending
Received
12 Feb 2026
Validated
12 Feb 2026
Ward
Marylebone
Postcode
W1H 1FQ

Site history

Applications at this address on the Westminster register

This site has had 4 applications since 2025: 3 approved, 0 refused.

  • 26/00814/ADLBC Granted

    51 Upper Montagu Street London W1H 1FQ

    Detailed drawings of new doors, new windows including sections and glazing bar profiles, new skirting, and cornices, new fireplace surrounds, new Juliette balconies pursuant to condition 4 of listed building consent dated 28 October 2025 (RN: 25/03875/LBC)

    Decided 7 Apr 2026 Conditions
  • 25/03875/LBC Granted

    51 Upper Montagu Street London W1H 1FQ

    Internal alterations including lowering of the floor level to the lower ground floor; Installation of replacement modern windows with slimline double-glazed units; external alterations to front and rear elevations to reinstate window baskets; installation of an air source heat pump and replacement of existing railings at main roof level; erection of the rear extension at lower ground floor level to include a green roof; and other associated works.

    Decided 6 Oct 2025 Heritage and listed buildings
  • 25/03874/FULL Granted

    51 Upper Montagu Street London W1H 1FQ

    Internal alterations including lowering of the floor level to the lower ground floor; Installation of replacement modern windows with slimline double-glazed units; external alterations to front and rear elevations to reinstate window baskets; installation of an air source heat pump and replacement of existing railings at main roof level; erection of the rear extension at lower ground floor level to include a green roof; and other associated works.

    Decided 7 Oct 2025 Full applications

Timeline

Dates from the published record

  1. 12 Feb 2026

    Received by Westminster

  2. 21 Jul 2026

    Added to PlanIndex

  3. Decision

    Awaiting decision

    Decision expected by 9 April 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 66 days over the applications it decided in the last year.

Cases linked to this one on the register

  • 25/03874/FULL Granted

    51 Upper Montagu Street London W1H 1FQ

    Internal alterations including lowering of the floor level to the lower ground floor; Installation of replacement modern windows with slimline double-glazed units; external alterations to front and rear elevations to reinstate window baskets; installation of an air source heat pump and replacement of existing railings at main roof level; erection of the rear extension at lower ground floor level to include a green roof; and other associated works.

    Decided 7 Oct 2025 Full applications

Who's behind it

Company information only, from the register and Companies House

ADL Planning Pty Ltd Agent, a planning consultancy

101 applications on PlanIndex · across 7 councils · 91% 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

11 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 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 91 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.

Nearby applications

Within 0.3 miles

  • 51 Upper Montagu Street London W1H 1FQ

    26/00814/ADLBC Submitted 11 Feb 2026 50 yards away

    Detailed drawings of new doors, new windows including sections and glazing bar profiles, new skirting, and cornices, new fireplace surrounds, new Juliette balconies pursuant to condition 4 of listed building consent dated 28 October 2025 (RN: 25/03875/LBC)

    Granted Conditions Windows or glazing 12 docs

  • 51 Upper Montagu Street London W1H 1FQ

    25/03875/LBC Submitted 9 Jun 2025 50 yards away

    Internal alterations including lowering of the floor level to the lower ground floor; Installation of replacement modern windows with slimline double-glazed units; external alterations to front and rear elevations to reinstate window baskets; installation of an air source heat pump and replacement of existing railings at main roof level; erection of the rear extension at lower ground floor level to include a green roof; and other associated works.

    Granted Heritage and listed buildings Extension Windows or glazing 37 docs

  • 51 Upper Montagu Street London W1H 1FQ

    25/03874/FULL Submitted 9 Jun 2025 50 yards away

    Internal alterations including lowering of the floor level to the lower ground floor; Installation of replacement modern windows with slimline double-glazed units; external alterations to front and rear elevations to reinstate window baskets; installation of an air source heat pump and replacement of existing railings at main roof level; erection of the rear extension at lower ground floor level to include a green roof; and other associated works.

    Granted Full applications Extension Windows or glazing 36 docs

  • 53 Upper Montagu Street London W1H 1SE

    25/05778/ADLBC Submitted 14 Aug 2025 50 yards away

    Details of the height and finished appearance of the new openings at ground and second floor levels, and proposed remedial works required to address damp following inspection works pursuant to Condition 2 (parts i and ii) of the listed building consent dated 2 January 2025 (RN: 24/05972/LBC)

    Granted Conditions 8 docs

  • Flat 19 York House 39 Upper Montagu Street London W1H 1FR

    25/06040/FULL Submitted 22 Aug 2025 50 yards away

    Installation of double glazed steel casement windows within the retained existing timber frames to front and rear of Flat 19.

    Granted Full applications Windows or glazing 25 docs

  • 56 Upper Montagu Street London W1H 1SN

    25/09343/LBC Submitted 24 Dec 2025 50 yards away

    90% 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 25/09342/FULL)

    Awaiting decision Heritage and listed buildings New dwelling Loft or dormer +2 21 docs

In Westminster

  • 26/06295/FULL Awaiting decision

    15 Warwick Way London SW1V 1QT

    Installation of a new shopfront with Medication Dispensing Outlet.

    Received 15 Sep, published by the council 17 Sep 2026 Full applications
  • 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.

    Received 15 Sep, published by the council 17 Sep 2026 Full applications
  • 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.

    Received 15 Sep, published by the council 22 Sep 2026 Full applications
  • 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)

    Received 15 Sep, published by the council 22 Sep 2026 Full applications
  • 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)

    Received 14 Sep, published by the council 22 Sep 2026 Full applications