20 Hertford Street London W1J 7RX

This site has had 3 applications since 2025.

• 26/00932/FULL Awaiting decision

  20 Hertford Street London W1J 7RX

  Replacement of existing timber-framed windows with new traditionally detailed timber windows matching the existing openings in size and opening style. Minor internal alterations to lower ground floor level, including the replacement of an existing window with a traditional door into the lightwell.

  Submitted 13 Feb 2026 Full applications
• 25/08992/CLOPUD Withdrawn

  20 Hertford Street London W1J 7RX

  Replacement of existing timber-framed windows with new traditionally detailed timber windows matching the existing openings in size and opening style, with a traditional glazing style.

  Decided 7 Mar 2026 Lawful development

1. 2 Dec 2025

   Received by Westminster

2. 20 Jul 2026

   Added to PlanIndex

3. Decision

   Awaiting decision

   Decision expected by 27 January 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 66 days over the applications it decided in the last year.

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 91 days. More in our guide to how long planning decisions take.

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.

• 20 Hertford Street London W1J 7RX

  25/08992/CLOPUD Submitted 11 Dec 2025 50 yards away

  Replacement of existing timber-framed windows with new traditionally detailed timber windows matching the existing openings in size and opening style, with a traditional glazing style.

  Withdrawn Lawful development Windows or glazing 32 docs

• 20 Hertford Street London W1J 7RX

  26/00932/FULL Submitted 13 Feb 2026 50 yards away

  87% historically approved · decision due ~10 Apr

  Replacement of existing timber-framed windows with new traditionally detailed timber windows matching the existing openings in size and opening style. Minor internal alterations to lower ground floor level, including the replacement of an existing window with a traditional door into the lightwell.

  Awaiting decision Full applications Windows or glazing 38 docs

• 17 Hertford Street London W1J 7RS

  26/06165/LBC Submitted 9 Sep 2026 50 yards away

  90% historically approved · decision due ~4 Nov

  Internal alterations to the basement including new lightweight timber-stud partitions to reorganise the existing basement layout; Installation of new sanitaryware in a newly configured bathroom; Replacement of modern kitchen fittings; and Installation of traditional four-panel timber doors, architraves and ironmongery designed to match existing doors.

  Awaiting decision Heritage and listed buildings

• 17 Hertford Street London W1J 7RS

  25/07827/FULL Submitted 29 Oct 2025 50 yards away

  87% historically approved · decision due ~1 Jan

  Internal restoration, redecoration and minor reconfigurations associated with the implementation of planning permission (24-03931-FULL) and listed building permission (24-03932-LBC); addition of a fourth-floor mansard roof to allow for the creation of a one-bedroom apartment for short term letting purposes; replacement of existing windows at third floor level with traditional timber sashes and other associated works. (Linked 25/07828/LBC)

  Awaiting decision Full applications Loft or dormer Windows or glazing 31 docs

• 17 Hertford Street London W1J 7RS

  25/07828/LBC Submitted 29 Oct 2025 50 yards away

  90% historically approved · decision due ~1 Jan

  Addition of a fourth-floor mansard roof to allow for the creation of a one-bedroom apartment for short term letting purposes, replacement of windows at third floor level, internal and external restoration, redecoration and minor reconfigurations and other associated works. (Linked with 25/07827/FULL)

  Awaiting decision Heritage and listed buildings Loft or dormer Windows or glazing 32 docs

• 17 Hertford Street London W1J 7RS

  26/03409/FULL Submitted 22 May 2026 50 yards away

  87% historically approved · decision due ~6 Aug

  Replacement of the mansard infill extension to the south east of the property by extending the existing bay upwards by a single storey (3-storeys total) and associated roof works to improve the internal space. (Linked with 26/03410/LBC)

  Awaiting decision Full applications Extension Loft or dormer 32 docs
  Small domestic

• 26/06295/FULL Awaiting decision

  15 Warwick Way London SW1V 1QT

  Installation of a new shopfront with Medication Dispensing Outlet.

  Received 15 Sep, published by the council 17 Sep 2026 Full applications
• 26/06297/FULL Awaiting decision

  15 Warwick Way London SW1V 1QT

  Alterations to rear elevation at basement level comprising replacement window and installation of double opening door.

  Received 15 Sep, published by the council 17 Sep 2026 Full applications
• 26/06294/FULL Awaiting decision

  15 Eaton Mews South London SW1W 9HP

  Installation of railings and sliding lantern light at main roof level in connection with the use of the roof as a terrace.

  Received 15 Sep, published by the council 22 Sep 2026 Full applications
• 26/06317/FULL Awaiting decision

  124 Hamilton Terrace London NW8 9UT

  Replacement of existing first-floor sash windows to the front and rear elevations with traditionally detailed painted timber, slim-profile double-glazed sash windows. (Linked to 26/06318/LBC)

  Received 15 Sep, published by the council 22 Sep 2026 Full applications
• 26/06273/FULL Awaiting decision

  9A Grosvenor Square London W1K 5AE

  Installation of natural Portland Stone paving to two front entrances. (Linked to 26/05473/LBC)

  Received 14 Sep, published by the council 22 Sep 2026 Full applications