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Flat 45 2 Mansfield Street London W1G 9NF

26/02044/FULLFull Planning Permission ApplicationApproved
Full

Approved on 25 June 2026

Site boundary (council red line)

Proposal

Roof extension to the existing mansard roof with associated elevational alterations on the Duchess Street and Rear Elevation, alterations to the existing mansard roof on the Mansfield Street Elevation including a new dormer window and the replacement of the existing external doors, two new rooflights at main roof level, installation of two external air conditioning (AC) condensers at main roof level, replacement of existing rooflights and windows, installation of new external cupboard at terrace level and internal reconfigurations throughout. (Linked with 26/02045/LBC)

Received
27 March 2026
Ward
Marylebone
Agent
Lucy Wood Architects
  1. Received27 Mar
  2. Validated27 Mar
  3. Consult.
  4. Target22 May
  5. Decided25 Jun

Decided in 90 days (council typically 49)

About this application

This is a full planning application for a dormer extension at Flat 45 2 Mansfield Street London W1G 9NF. Westminster has handled 4,484 applications of this type. This one was decided in 90 days, 6 weeks longer than Westminster's typical decision time. The site is in the Harley Street conservation area, with 20 listed buildings nearby. There has been 1 other application at this address. In the past year there have been 168 applications across Marylebone. We hold 590 applications in total for the W1G postcode area.

86% of full applications at City of Westminster were approved. Across all application types, the council typically decides in about 7 weeks (median).

Based on decided applications received in the last 3 years.Planning something similar? See what gets approved on your street

Application details

Postcode
W1G 9NF
Application type
Full Planning Permission Application
Scale / size
Small

Planning application dates

Date validated
27 March 2026
Target decision date
22 May 2026

Applicant and agent

Agent
Lucy Wood Architects
Architect profile
LUCY WOOD ARCHITECTS LTD
Agent address
1 18 Britten Street London SW3 3TU

Planning decision

Statutory period
56 days

Additional information

Planning Portal ID
PP-14738550
Comments
0
Documents
12

Site constraints

Checking the site
2/3
Council recordsAppealsFlood risk

Designations that overlap or adjoin the site outline.

  • Conservation area: Harley Street
  • Listed building: Grade II: No 2 and Attached Railings No 4 and Attached RailingsOn this site · +4 more
  • Article 4 direction: Article 4 Basement Development Permitted Rights Removed
  • Tree Preservation Order: Ref W324Protected tree on or next to this site · +1 more
  • Flood zone 1: Low probability (rivers and sea)
Also checked, none recorded (20)

flood storage areas, green belt, scheduled monuments, World Heritage Sites, World Heritage Site buffer zones, registered parks and gardens, registered battlefields, Heritage at Risk entries, nutrient neutrality catchments, national parks, National Landscapes, SSSIs, Special Areas of Conservation, Special Protection Areas, Ramsar sites, ancient woodland, national nature reserves, local nature reserves, heritage coasts and brownfield registers.

A guide only, from official open data; it is not a planning search. Flood zones cover rivers and sea, not surface water.

Data © Crown copyright and others · sources and licences

Contains public sector information from planning.data.gov.uk (MHCLG and local planning authorities), licensed under the Open Government Licence v3.0. © Crown copyright and database right 2026.

© Historic England 2026. Contains Ordnance Survey data © Crown copyright and database right 2026. The Historic England GIS Data contained in this material was obtained on 2026-11-03. The most publicly available up to date Historic England GIS Data can be obtained from HistoricEngland.org.uk.

© Natural England copyright. Contains Ordnance Survey data © Crown copyright and database right 2026.

© Environment Agency copyright and/or database right 2026. All rights reserved. Flood Map for Planning, Open Government Licence v3.0.

Contains Ordnance Survey data © Crown copyright and database right 2026.

Source: Office for National Statistics licensed under the Open Government Licence v.3.0. Contains OS data © Crown copyright and database right 2026.

Associated applications

  1. 2026
    27 Mar

    Roof extension to the existing mansard roof with associated elevational alterations on the Duchess Street and…

    This applicationApprovedFull26/02044/FULL
  2. 2026
    27 Mar

    Roof extension to the existing mansard roof with associated elevational alterations on the Duchess Street and…

    ApprovedListed building consentPart of26/02045/LBC

Source: Westminster

Contains public sector information from the Planning London Datahub, licensed under the Open Government Licence v3.0.

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