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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 6 applications since 2025: 3 approved, 0 refused.

  • 26/07161/LBC Awaiting decision

    51 Upper Montagu Street London W1H 1FQ

    Internal alterations to include additional floor lowering within the lower ground floor WC to match the consented level of the other rooms.

    Submitted 19 Oct 2026 Heritage and listed buildings
  • 26/06443/ADFULL Awaiting decision

    51 Upper Montagu Street London W1H 1FQ

    Details of Desktop study and Site investigation reports pursuant to partial discharge of Condition 11 (Phase 2 and Phase 3) of planning permission dated 24th October 2025 (RN: 25/03874/FULL).

    Submitted 21 Sep 2026
  • 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 91 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

105 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 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.

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

    26/07161/LBC Submitted 19 Oct 2026 50 yards away

    90% historically approved · decision due ~18 Dec

    Internal alterations to include additional floor lowering within the lower ground floor WC to match the consented level of the other rooms.

    Awaiting decision Heritage and listed buildings

  • 51 Upper Montagu Street London W1H 1FQ

    26/06443/ADFULL Submitted 21 Sep 2026 50 yards away

    89% historically approved · decision due ~16 Nov

    Details of Desktop study and Site investigation reports pursuant to partial discharge of Condition 11 (Phase 2 and Phase 3) of planning permission dated 24th October 2025 (RN: 25/03874/FULL).

    Awaiting decision

  • 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

In Westminster

  • 26/07528/FULL Awaiting decision

    69 Eaton Place London SW1X 8DF

    Installation of new cast iron water pipe on rear courtyard elevation. (Linked with 26/07529/LBC)

    Received 5 Nov, published by the council 6 Nov 2026 Full applications
  • 26/05200/FULL Decided

    1 The Court House 165 Seymour Place London W1H 4PU

    Installation of waterproofing system to the existing lead flat roofs

    Received 3 Aug, published by the council 28 Aug 2026 Full applications
  • 26/07521/FULL Awaiting decision

    Flat 18 Harlequin Court 20 Tavistock Street London WC2E 7NZ

    Installation of one external condenser unit

    Received 4 Nov, published by the council 6 Nov 2026 Full applications
  • 26/07508/FULL Awaiting decision

    Buckingham Palace The Mall London SW1A 1AA

    Replacement of existing security lighting to the Buckingham Palace Forecourt with 80 compact LED spotlights installed within the lantern clusters across 10 principal piers, with associated concealed cabling and reversible fixings. (Linked with 26/07509/LBC)

    Received 4 Nov, published by the council 5 Nov 2026 Full applications
  • 26/07472/FULL Awaiting decision

    Flat 3 82 New Cavendish Street London W1G 9TA

    Replacement windows to second floor level with vacuum, double glazing windows. (Linked with 26/07473/LBC)

    Received 3 Nov, published by the council 6 Nov 2026 Full applications