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Planning application

51 Upper Montagu Street London W1H 1FQ

Granted Westminster 25/03874/FULL Full Planning Permission Application

Works: Extension Windows or glazing

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

Proposal

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.

As published by the council, reference 25/03874/FULL

Application record

Reference
25/03874/FULL
Type
Full Planning Permission Application
Status
Decided
Decision
Application Permitted
Received
9 Jun 2025
Validated
9 Jun 2025
Decided
7 Oct 2025
Ward
Marylebone
Decision by
Complex 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
  • 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

Timeline

Dates from the published record

  1. 9 Jun 2025

    Received by Westminster

  2. 7 Oct 2025

    Decision issued: Application Permitted

  3. 30 Aug 2026

    Added to PlanIndex

Cases linked to this one on the register

1 later application on the register refers to this one:

  • 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

Who's behind it

Company information only, from the register and Companies House

Agent on file, a planning consultancy

44 applications on PlanIndex · across 5 councils · 100% granted

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Documents

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

36 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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What this grant of permission means

Westminster granted permission on 7 October 2025, 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 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 500 metres

  • 51 Upper Montagu Street London W1H 1FQ

    25/03875/LBC Submitted 9 Jun 2025 1m 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

  • 53 Upper Montagu Street London W1H 1SE

    25/05778/ADLBC Submitted 14 Aug 2025 6m 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

  • 51 Upper Montagu Street London W1H 1FQ

    26/00898/ADFULL Submitted 12 Feb 2026 15m 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

    26/00814/ADLBC Submitted 11 Feb 2026 15m 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

  • 57A Upper Montagu Street London W1H 1SG

    26/00135/LBC Submitted 12 Jan 2026 17m away

    90% historically approved · decision due ~1 Apr

    Replacement of two windows on the rear elevation with timber double-glazed sash windows.

    Awaiting decision Heritage and listed buildings Windows or glazing 14 docs

  • 56 Upper Montagu Street London W1H 1SN

    25/09343/LBC Submitted 24 Dec 2025 34m 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

  • 26/06024/FULL Awaiting decision

    House Of Commons Palace Of Westminster Parliament Square London SW1A 0AA

    Installation of new and replacement electronic equipment within Speaker. (Linked with 26/06025/LBC)

    3 Sep 2026 Full applications
  • 26/06017/FULL Awaiting decision

    38 Lauderdale Mansions Lauderdale Road London W9 1NE

    Installation of an external AC Unit / Heat Pump at roof level.

    2 Sep 2026 Full applications
  • 26/05938/FULL Awaiting decision

    24 Vincent Square London SW1P 2NJ

    Subdivision of existing residential property to create two self-contained 3-bedroom family homes, along with cycle parking and associated external alterations.

    1 Sep 2026 Full applications
  • 26/05935/FULL Awaiting decision

    47 Hereford Road London W2 5AH

    Installation of one number new external condenser unit to the southerly elevation service alley.

    1 Sep 2026 Full applications
  • 26/05959/FULL Awaiting decision

    Basement And Ground Floor 50 New Bond Street London W1S 1BJ

    Installation of three new condensers on the roof, within an existing designated plant area.

    1 Sep 2026 Full applications