11 Marylebone Mews London W1G 8PX Data via plota.co.uk

26/07360/FULL - Full Planning Permission Application Pending
Admin / procedural

Proposal

Variation of condition 1 of planning permission dated 02 July 2026 (RN 26/00802/FULL) for the Erection of a mansard roof extension, excavation and extension of the existing basement, installation of plant within a louvered acoustic enclosure on the rear flat roof at second floor and the replacement of the fenestration to the front and rear of the building; all to enlarge and alter dwellinghouse (Class C3). NAMELY, amendments to the layout and design of the mansard to the rear. Data via plota.co.uk

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View original council record ↗Last checked

Application progress

✓
Received
27 Oct 2026
✓
Consultation
2 Nov 2026
Decision
Expected by 22 Dec 2026

Under consideration

No decision has been issued yet. A decision is expected by 22 Dec 2026.

Comments are open until 2 Dec 2026

Comment on this application ↗

Documents 19

Statements & assessments 4

PDF PLANNING STATEMENT Background Papers · 27 Oct 2026 View ↗ PDF FIRE SAFETY - REASONABLE EXCEPTION STATEMENT Background Papers · 27 Oct 2026 View ↗ PDF WCC SUSTAINABLE DESIGN STATEMENT Background Papers · 27 Oct 2026 View ↗ PDF HERITAGE STATEMENT Heritage Statement · 27 Oct 2026 View ↗

Plans & drawings 6

PDF EXISTING LOCATION PLAN Drawing · 27 Oct 2026 View ↗ PDF EXISTING SITE PLAN Drawing · 27 Oct 2026 View ↗ PDF PROPOSED FIRST AND SECOND FLOOR PLANS Drawing · 27 Oct 2026 View ↗ PDF PROPOSED ROOF PLAN (1) Drawing · 27 Oct 2026 View ↗ PDF PROPOSED ELEVATIONS (2) Drawing · 27 Oct 2026 View ↗ PDF PROPOSED SECTIONS (1) Drawing · 27 Oct 2026 View ↗

Application forms 2

PDF APPLICATIONFORMREDACTED Application Form · 27 Oct 2026 View ↗ PDF FEECALCULATION Background Papers · 27 Oct 2026 View ↗

Consultation & comments 1

PDF NEIGHBOUR NOTIFICATION LETTER (21D) Background Papers · 2 Nov 2026 View ↗

Other documents 6

PDF RECEIPT OF APPLICATION Other · 2 Nov 2026 View ↗ PDF ACK-GENERAL LETTER (G/P/C) Background Papers · 2 Nov 2026 View ↗ PDF CNSLT-LA SOCIETY Background Papers · 2 Nov 2026 View ↗ PDF SITE NOTICE 21 OR 28 DAYS IF T&C APPL. Background Papers · 2 Nov 2026 View ↗ PDF ATTACHMENTSUMMARY Background Papers · 27 Oct 2026 View ↗ PDF DAYLIGHT AND SUNLIGHT REPORT - DATED 22 SEPTEMBER 2026 Background Papers · 27 Oct 2026 View ↗

All documents on the council site ↗

Associated applications 2

Site constraints 9

Harley Street 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 ↗
2 Article 4 directions
Article 4 Basement Development Permitted Rights Removed · Article 4 Direction Class E To C3 In Central Activities Zone. 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 ↗
71 listed buildings within 150 m
Nearest: 67, Wimpole Street W1, Grade II, 5 m away · 1 Grade II*, 70 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 71 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
National infrastructure project 1846 m away: Thames Tideway Tunnel; Inside the City of Westminster built-up area; Public transport access: PTAL 6a (excellent), TfL 2023, for the 100 m square; Town centre 100 m away: Marylebone High Street.
Not affected
Outside flood zones 2 and 3 · Not green belt · No scheduled monument at the site

Checked on 3 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 area133 m² (1,432 sq ft)
Energy ratingE (54 out of 100), could reach B
PropertyMid-terrace house, 4 habitable rooms
BuiltBefore 1900
HeatingBoiler and radiators, mains gas
WallsSolid brick, as built, no insulation (assumed)

From the energy performance certificate lodged in August 2021, the latest held for this property. The building may have changed since. View the certificate

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Important details

Council
Westminster
Application type
Full Planning Permission Application
Postcode
W1G 8PX
Received
27 Oct 2026
Validated
27 Oct 2026
Ward
Marylebone
Case officer
Show
Target decision
22 Dec 2026
Applicant
Show
Agent
AD Heritage Planning

Public comments

No public comments yet.

3 neighbours consulted · Last counted 3 Nov 2026

Read the comments on the council site ↗

Consultation & key dates

Alt. reference
PP-15328543
Planning Portal ref
PP-15328543
Comments by
2 Dec 2026
Site or press notice
2 Nov 2026
Env. assessment
No

Historical activity at this location

26 previous applications on record - archival context, not part of the live application.

This property

Previous applications at this address

2025
Creation of an additional floor via the erection of a mansard roof and extension of an ex…
25/03462/FULL
Within ~100m

Nearby activity

2025
44 Welbeck Street London W1G 8DY
Repositioning of third-floor kitchenette door; Installation of a fire door and associated…
25/08107/LBC
2025
58 Queen Anne Street London W1G 8HW
Minor internal alterations to the building involving the introduction of double doors at…
25/08051/LBC
2025
45 New Cavendish Street London W1G 9TJ
Internal alterations at ground and lower ground level including reinstatement of staircas…
25/07902/LBC
2025
45 New Cavendish Street London W1G 9TJ
Use of part of the lower ground floor for retail purposes (Class E). (Linked with 25/0790…
25/07901/FULL
2025 Approved
Hahnemann House 32 Welbeck Street London W1G 8EU
Display for a temporary period of six months of a non-illuminated 'to let' board attached…
25/06276/AD7
2025 Refused
30 Queen Anne Street London W1G 8HX
Erection of an infill extension at basement and ground floor level, Installation of a new…
25/05505/FULL
2025
17 Welbeck Street London W1G 9XJ
Installation of five condenser units to internal lightwell and internal fan coil units wi…
25/06438/LBC
2025
45 Welbeck Street London W1G 8DZ
Replacement of windows with slimline double glazing windows and associated works.
25/06314/FULL
2025
Hahnemann House 32 Welbeck Street London W1G 8EU
Installation of CCTV to front entrance and rear emergency exit. (Retropsective) Linked wi…
25/06098/LBC
2025
Hahnemann House 32 Welbeck Street London W1G 8EU
Installation of CCTV to front entrance and rear emergency exit. (Retrospective) Linked wi…
25/06097/FULL
2025
45 Welbeck Street London W1G 8DZ
Replacement of windows with slimline double glazing windows and associated works. (Linked…
25/05979/LBC
2025 Approved
58 Queen Anne Street London W1G 8HW
Minor internal alterations to replace the existing asbestos doors in the building
25/03879/LBC
2025 Refused
Hahnemann House 32 Welbeck Street London W1G 8EU
Installation of CCTV to front entrance and rear emergency exit. (Retrospective, linked wi…
25/04216/FULL
2025 Refused
Hahnemann House 32 Welbeck Street London W1G 8EU
Installation of CCTV to front entrance and rear emergency exit. ((Retrospective, Linked w…
25/04217/LBC
2025 Approved
69 Wimpole Street London W1G 8AS
Installation of 2no. wall mounted air source heat pumps within an acoustic enclosure at r…
25/03649/FULL
2025 Approved
69 Wimpole Street London W1G 8AS
Installation of 2no. air source heat pumps within an acoustic enclosure.
25/03650/LBC
2025 Approved
3 Bulstrode Street London W1U 2JB
Internal works to re-configure the existing apartment including the removal of an existin…
25/01841/LBC
2025
50 Queen Anne Street London W1G 9LA
Installation of new air source heat pump to existing plant enclosure to rear roof; format…
25/02536/LBC
2025
50 Queen Anne Street London W1G 9LA
Installation of new air source heat pump to existing plant enclosure and roof light to re…
25/02535/FULL
2025
Basement And Ground Floor 45 Welbeck Street London W1G 8DZ
Internal alterations at ground and lower ground floor.
25/02269/LBC
2021 Approved
28 Harley Place London W1G 8LZ
Internal alterations at all floor levels and installation of replacement rooflights.
21/01760/LBC
2021 Refused
28 Harley Place London W1G 8LZ
Use of the building as a dentist (Class E).
21/01759/FULL
2021
First Floor Flat 66 Wimpole Street London W1G 8AW
Insertion of windows into internal lightwell, and modifications to rear terrace.
21/04219/FULL
2021 Refused
29 Wimpole Street London W1G 8GP
Internal refurbishment works to second floor flat, including re-plastering walls and ceil…
21/03384/LBC
2021 Approved
44 Welbeck Street London W1G 8DY
Removal of condition 4 of (20/03696/LBC) Retention of rooflight
21/01835/LBC
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.