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Planning application

51 Upper Montagu Street London W1H 1FQ

Granted Westminster 26/00814/ADLBC Approval of Details (ADLBC)

Works: Windows or glazing

Relates to 25/03875/LBC

Permission granted. Work must normally begin within three years of the decision or the permission lapses.

Proposal

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)

As published by the council, reference 26/00814/ADLBC

Application record

Reference
26/00814/ADLBC
Type
Approval of Details (ADLBC)
Status
Decided
Decision
Granted As published: Application Permitted
Received
11 Feb 2026
Validated
11 Feb 2026
Decided
7 Apr 2026
Ward
Marylebone
Decision by
Delegated Decision
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.

  • 26/00898/ADFULL Awaiting decision

    51 Upper Montagu Street London W1H 1FQ

    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).

    Submitted 12 Feb 2026 Full applications
  • 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. 11 Feb 2026

    Received by Westminster

  2. 7 Apr 2026

    Decision issued: Application Permitted

  3. 21 Jul 2026

    Added to PlanIndex

Cases linked to this one on the register

  • 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

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

12 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 this grant of permission means

Westminster granted permission on 7 April 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 condition discharge and variation applications

This application deals with conditions on an existing permission, supplying the details a condition requires or asking to vary or remove one, without reopening the permission itself. More in our guide to planning application types.

Nearby applications

Within 0.3 miles

  • 51 Upper Montagu Street London W1H 1FQ

    26/00898/ADFULL Submitted 12 Feb 2026 50 yards away

    87% historically approved · decision due ~9 Apr

    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).

    Awaiting decision Full applications Windows or glazing 11 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

  • 26/04860/ADLBC Granted

    New Zealand House 80 Haymarket London SW1Y 4TE

    Details of external and internal signage strategy pursuant to Condition 7(E) of listed building consent dated 12th February 2021 (RN: 19/07816/LBC)

    Received 20 Jul, published by the council 1 Aug 2026 Conditions
  • 26/04843/ADLBC Granted

    New Zealand House 80 Haymarket London SW1Y 4TE

    Detailed design and specification of new blinds to NZH based on mock-up trials on-site pursuant to Condition 6(m) of listed building consent dated 12th February 2021 (19/07816/LBC).

    Received 20 Jul, published by the council 1 Aug 2026 Conditions
  • 26/05026/ADLBC Awaiting decision

    St James's Park The Mall London SW1A 1AA

    Details of method statement for re-carving works pursuant to condition 3(i) of listed building consent dated 16 July 2026 (RN: 26/03399/LBC)

    Received 27 Jul, published by the council 4 Aug 2026 Conditions
  • 26/04850/ADLBC Awaiting decision

    17 Belgrave Square London SW1X 8PG

    Detailed drawings of garage doors, roof lantern and any new lighting and flooring in the principal rooms pursuant to condition 6 (iii) (iv) (v) of listed building 18th August 2025 (RN:25/03417/LBC)

    Received 20 Jul, published by the council 1 Aug 2026 Conditions
  • 25/07120/ADLBC Granted

    72 - 74 Lancaster Gate London W2 3NH

    Details of new and altered doors and door architraves, including external faces of lifts (detailed elevations and sections at 1:10) pursuant to Condition 3 (A) of Listed Building Consent dated 14 December 2023 (RN: 23/00772/LBC) (Linked app: 25/07088/ADFULL)

    Received 2 Oct, published by the council 21 Jul 2026 Conditions