11 Montagu Mews South London W1H 7ER Data via plota.co.uk

26/03408/FULL - Full Planning Permission Application Approved
Extensions & alterations

Proposal

Installation of replacement double glazed windows. Data via plota.co.uk

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View original council record ↗Last checked

Application progress

✓
Received
22 May 2026
✓
Consultation
1 Jul 2026
✓
Approved
5 Aug 2026

Approved on 5 Aug 2026 · Delegated Decision · Last checked 7 Aug 2026

Documents 14

Decision & officer reports 2

PDF GRANT OF FULL PP [PE] Decision Notice · 5 Aug 2026 View ↗ PDF DELEGATED REPORT Report · 5 Aug 2026 View ↗

Statements & assessments 1

PDF DESIGN AND ACCESS STATEMENT Design and Access Statement · 22 May 2026 View ↗

Plans & drawings 5

PDF LOCATION PLAN Location Plan · 22 May 2026 View ↗ PDF PROPOSED WINDOW DETAIL_101 Drawing · 22 May 2026 View ↗ PDF PROPOSED PLANS Drawing · 22 May 2026 View ↗ PDF EXISTING PLANS Drawing · 22 May 2026 View ↗ PDF EXISTING AND PROPOSED WINDOW ELEVATION Drawing · 22 May 2026 View ↗

Application forms 1

PDF APPLICATIONFORMREDACTED Application Form · 22 May 2026 View ↗

Consultation & comments 1

PDF NEIGHBOUR NOTIFICATION LETTER (21D) Background Papers · 1 Jul 2026 View ↗

Other documents 4

PDF ACK-GENERAL LETTER (G/P/C) Background Papers · 1 Jul 2026 View ↗ PDF CNSLT-LA SOCIETY Background Papers · 1 Jul 2026 View ↗ PDF SITE NOTICE 21 OR 28 DAYS IF T&C APPL. Background Papers · 1 Jul 2026 View ↗ PDF RECEIPT OF APPLICATION Other · 28 May 2026 View ↗

All documents on the council site ↗

Site constraints 9

Portman Estate conservation area
Demolition needs planning permission and permitted development is restricted.
The council must give weight to preserving or enhancing the area's character and appearance. Not every council has published its boundaries as open data.
Council document ↗
Article 4 direction
Article 4 Basement Development Permitted Rights Removed. Named permitted development rights are withdrawn here.
An Article 4 direction withdraws particular permitted development rights, so work that would normally need no application needs one here. Not every council has published its directions.
Air quality management area: Westminster AQMA
The council has declared the area as failing an air quality objective.
Schemes that add traffic, parking or combustion plant are assessed against the area's action plan and may need an air quality assessment.
Council record ↗
44 listed buildings within 150 m
Nearest: 19, Montagu Street W1, Grade II, 17 m away · 44 Grade II
The site itself is not listed. Listed building consent is needed for work that affects the special interest of a listed building, inside or out, on top of planning permission. Setting can be a consideration for buildings nearby; there is no fixed radius.
Show all 44 with distances
Historic England ↗
Central activities zone
The core of central London in the London Plan.
Offices, culture and the other strategic functions of the centre take priority over new housing here.
Also on the record
Registered park or garden 196 m away: Portman Square and Manchester Square; National infrastructure project 98 m away: London Strategic Heat Main Project, at pre-application; Inside the City of Westminster built-up area; Public transport access: PTAL 6b (excellent), TfL 2023, for the 100 m square.
Not affected
Outside flood zones 2 and 3 · Not green belt · No scheduled monument at the site

Checked on 2 November 2026. Historic England, the Environment Agency, Natural England, the Planning Inspectorate, Transport for London (public transport access levels, Powered by TfL Open Data, OGL v3.0, contains OS data © Crown copyright and database right 2025) and council datasets, Open Government Licence. A boundary can run through a site and the council holds the definitive record: confirm with the council before relying on this.

Building

Floor area76 m² (818 sq ft)
Energy ratingD (58 out of 100), could reach B
PropertyEnd-terrace house, 3 habitable rooms
BuiltBefore 1900
HeatingBoiler and radiators, mains gas
WallsSolid brick, as built, no insulation (assumed)

From the energy performance certificate lodged in November 2019, the latest held for this property. The building may have changed since. View the certificate

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Other new applications on this street

2 Jun 2026Approved

15 - 16 Montagu Mews South London W1H 7ET

Details of all new windows, omission of the rooflight to the front roof slope co...

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15 May 2026Pending

8 Montagu Mews West London W1H 2EE

Erection of a single-storey roof extension, installation of air conditioning pla...

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30 Oct 2026Pending

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30 Oct 2026Pending

39 Montagu Square London W1H 2LL

Amalgamation of Flats 3 and 4 to form one single dwelling including associated i...

26/07416/LBC
29 Oct 2026Pending

Flat 6 15 Fitzhardinge Street London W1H 6EQ

Replacement of existing timber sash windows with slim double glazed timber sash ...

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29 Oct 2026Pending

Flat 6 15 Fitzhardinge Street London W1H 6EQ

Replacement of existing timber sash windows with slim double glazed timber sash ...

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28 Oct 2026Pending

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Use of the building as an embassy (sui generis)

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27 Oct 2026Pending

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Details of a methodology, where applicable, and detailed drawings (Scale 1:20 an...

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Important details

Council
Westminster
Application type
Full Planning Permission Application
Postcode
W1H 7ER
Received
22 May 2026
Validated
22 May 2026
Ward
Marylebone
Case officer
Show
Target decision
17 Jul 2026
Decision
Application Permitted
Decision date
5 Aug 2026
Decision level
Delegated Decision
Applicant
Show
Agent
Quatrefoils Ltd

How this decision compares

Decided in 75 days from validation, 20 days slower than Westminster's median of 55 for extensions. Approved, as 88% of extensions here are.

56%decided within 8 weeks
88%approved
1,937decided in the last year

Plota live figures for extensions decided by Westminster in the last twelve months, from validation. Westminster decision record →

Public comments

No public comments yet.

8 neighbours consulted · Last counted 7 Aug 2026

Read the comments on the council site ↗

Consultation & key dates

Alt. reference
PP-14953248
Planning Portal ref
PP-14953248
Comments by
29 Jul 2026
Site or press notice
1 Jul 2026
Env. assessment
No

Historical activity at this location

25 nearby applications on record - archival context, not part of the live application.

Within ~100m

Nearby activity

2025 Approved
Rutland Court 64 Upper Berkeley Street London W1H 7QT
Installation of a single wrought iron gate at the entrance to the passageway leading to a…
25/06129/FULL
2025 Approved
26 Montagu Mews South London W1H 7ES
Replacement of garage doors with timber windows.
25/05187/FULL
2025
Basement And Ground Floor 67 Upper Berkeley Street London W1H 7QX
Display for a temporary period of six months of a non-illuminated estate agent board loca…
25/07459/AD7
2025
Basement And Ground Floor 67 Upper Berkeley Street London W1H 7QX
Display for a temporary period of six months of a non-illuminated estate agent board loca…
25/07458/AD7
2025
42 Great Cumberland Place London W1H 7TP
Repair of six vaults and associated works.
25/07213/LBC
2025 Approved
Flat 4 58 Montagu Square London W1H 2LS
Internal alterations to flat at fourth floor level including installation of a spiral sta…
25/04771/LBC
2025 Approved
8 Montagu Mews South London W1H 7ER
Gas meter relocation to the front facade
25/04796/FULL
2025 Withdrawn
26 Montagu Mews South London W1H 7ES
Alteration of existing coach house/garage to kitchen and living room with new painted tim…
25/04074/CLOPUD
2025
Flat 2 13 Montagu Street London W1H 7EX
Installation of airbrick to front elevation, new secondary glazing, reconfiguration, acou…
25/04426/LBC
2025
Flat 2 13 Montagu Street London W1H 7EX
Installation of airbrick to front elevation, new secondary glazing, reconfiguration, acou…
25/04425/FULL
2025 Approved
68 Great Cumberland Place London W1H 7TX
1 x Japanese maple (T2): Reduce all round by approx. 1m, leaving furnishing growth . Thin…
25/03179/TCA
2025
Flat 4 1 Bryanston Square London W1H 2DH
Internal alterations including new partitions, joinery and cornices, kitchen and bathroom…
25/01336/LBC
2025
12 Upper Berkeley Street London W1H 7QD
Display for a temporary period of six months of a non-illuminated estate agent board atta…
25/01287/AD7
2025
Flat 7 1 Bryanston Square London W1H 2DH
Replacement of two rooflights and two crittal windows with timber box sash windows and re…
25/01181/LBC
2025
37 Great Cumberland Place London W1H 7TD
Installation of a water misting system throughout the building.
25/00930/LBC
2025
37 Great Cumberland Place London W1H 7TD
Introduction of three new anchor posts on the main roof and additional concealed eye bolt…
25/00916/LBC
2024
3 Brunswick Mews London W1H 7FB
Erection of new mansard roof extension.
24/08923/FULL
2024 Refused
37 Great Cumberland Place London W1H 7TD
Installation of an internal fire suppression system at all floor levels.
24/02837/LBC
2024
37 Great Cumberland Place London W1H 7TD
Removal of Condition 3(d) of listed building consent dated 15 October 2020 (RN: 20/03651/…
24/03886/LBC
2024 Approved
Flat 2 16 Montagu Street London W1H 7EX
Replacement of all windows to double glazed units.
24/01344/FULL
2018 Approved
49 Bryanston Square London W1H 7LL
Replacement of the pitched roof coverings inclusing lead flashing and coping stones and r…
18/00375/LBC
2017 Approved
Flat 3 2 Bryanston Square London W1H 2DH
Replacement of a corner bay window with timber window, installation of secondary glazing…
17/10370/LBC
2017 Approved
Flat 3 2 Bryanston Square London W1H 2DH
Replacement of a corner bay window with timber window, installation of secondary glazing…
17/10369/FULL
2017 Approved
2 Montagu Mews West London W1H 2EE
Variation of condition 1 and 3 of planning permission dated 03 November 2015 (RN: 15/0552…
17/09539/FULL
2017 Approved
12 Montagu Mews South London W1H 7ER
Alterations to convert garage to residential floorspace (Class C3), replacement and reloc…
17/09588/FULL
Westminster
Planning Authority Score
3.5/10
Below average
#221 of 296 councils
Relevant to this application:
Householder decisions

Westminster is slower than most councils at deciding householder applications, ranking #258 out of 296. Only 28% of applications have the time limit extended, well below the 41% national average - the council usually decides on time. Westminster is also one of the strictest councils - it refuses more householder applications than almost any other, with only 81% approved vs 90% nationally.

One of the strictest councils
only 81% approved vs 90% nationally
These figures are council-wide context, not a prediction for this application. View full council performance
Westminster decision statistics
Based on MHCLG data, the year to March 2026
86%
Overall approval rate
Below avg (87%) #201 of 296
81%
Householder approved
Below avg (90%) #277 of 296
44%
Decided in 8 weeks
Below avg (63%) #258 of 296
28%
Extended time limit
Below avg (41%) #46 of 296
83%
Minor dwellings approved
12 decided (1-9 homes)
67%
Major dwellings approved
3 decided (10+ homes)
81%
Change of use approved
133 decided
4,602
Total decisions
648 refused in the year to March 2026
Source: MHCLG planning statistics · See full council rankings

Energy performance: Energy performance certificates from the Energy Performance of Buildings Register, Ministry of Housing, Communities and Local Government. Contains public sector information licensed under the Open Government Licence v3.0. © Crown copyright 2026.