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Halcyon London International School 33 Seymour Place London W1H 5AP

25/08138/ADLBCApproval of Details (ADLBC)Approved
Discharge / amendments

Approved on 17 February 2026

Approximate site (title boundary)
Boundary © HM Land Registry, © Ordnance Survey · details

This information is subject to Crown copyright and database rights 2026 and is reproduced with the permission of HM Land Registry. The polygons (including the associated geometry, namely x, y co-ordinates) are subject to Crown copyright and database rights 2026 Ordnance Survey AC0000851063. Conditions of use.

Proposal

Detailed drawings (scaled sections and elevations) of the stained-glass light boxes & fixing details pursuant to condition 3 of listed building dated 3rd February 2025 (RN:24/08169/LBC)

Received
7 November 2025
Ward
Marylebone
Agent
ADAM Architecture
  1. Received7 Nov
  2. Validated7 Nov
  3. Consult.
  4. Target2 Jan
  5. Decided17 Feb

Decided in 102 days (council typically 49)

About this application

This is an application to discharge conditions at Halcyon London International School 33 Seymour Place London W1H 5AP. Westminster has handled 3,063 applications of this type. This one was decided in 102 days, 8 weeks longer than Westminster's typical decision time. The site is in the Portman Estate conservation area, with 13 listed buildings nearby. There has been 1 other application at this address. In the past year there have been 171 applications across Marylebone. We hold 896 applications in total for the W1H postcode area.

92% of conditions 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.See what's approved near your address

Application details

Postcode
W1H 5AP
Application type
Approval of Details (ADLBC)
Scale / size
Small

Planning application dates

Date validated
7 November 2025
Target decision date
2 January 2026

Applicant and agent

Agent
ADAM Architecture
Architect profile
ADAM ARCHITECTURE LIMITED
Agent address
West Wing Somerset House Strand London WC2R 1LA United Kingdom

Planning decision

Statutory period
56 days

Additional information

Planning Portal ID
PP-14423029
Comments
0
Documents
6

Site constraints

Checking the site
2/3
Council recordsAppealsFlood risk

Designations that overlap or adjoin the site outline.

  • Conservation area: Portman Estate
  • Listed building: Grade II: 29 and 30, Upper Berkeley Street W1On or next to this site · +2 more
  • Article 4 direction: Article 4 Basement Development Permitted Rights Removed
  • Brownfield land register: 33 Seymour Place London W1H 5APRegister site at or near this address
  • Flood zone 1: Low probability (rivers and sea)
Also checked, none recorded (20)

flood storage areas, tree preservation orders, 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 and heritage coasts.

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.

Source: Westminster

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

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