Planning application
26/03509/FULL
20 - 21 Cavendish Square London W1G 0RN
Proposal
Installation of replacement roof top plant with a dummy mansard roof extension, replacement plant at ground floor and new third floor roof structure and new substation at the lower ground floor. [Linked to 26/03510/LBC]
As published by the council, reference 26/03509/FULL
Timeline
Dates from the published record
-
28 May 2026
Received by Westminster
-
21 Jul 2026
Added to PlanIndex
-
Decision
Awaiting decision
The statutory target is eight weeks for most applications and thirteen for major development. Extensions of time are common.
What happens while it is decided
The process from here
This application is with Westminster for determination. The council publicises it, consults neighbours and technical bodies where required, and weighs the responses against local and national planning policy.
The statutory target is eight weeks for most applications and thirteen for major development, though extensions of time are common. Comments carry most weight while the case is undecided, so check the council portal for the deadline if you want to respond.
About full applications applications
How this application type works
A full application seeks permission for a complete, detailed proposal in one go: siting, design, access and landscaping are all fixed at this stage. It is the standard route for new buildings, conversions and changes of use. The statutory target is eight weeks for smaller schemes and thirteen weeks for major development, though complex cases often take longer by agreement.
Nearby applications
Within 500 metres
-
26/03232/ADV Awaiting decision
20 - 21 Cavendish Square London W1G 0RN
Display of a flag measuring 2.15m x 1.12m.
-
26/03510/LBC Awaiting decision
20 - 21 Cavendish Square London W1G 0RN
Installation of replacement roof top plant with a dummy mansard roof extension, replacement plant at ground floor and new third floor roof structure and new substation at the lower ground floor. [Linked to 26/03509/FULL]
-
25/06186/LBC Granted
Cavendish House 18 Cavendish Square London W1G 0PJ
Removal of double doorway with surrounding frame and glazing, provision of matwell, refurbishment of C20th and C21st elements.
-
03/08496/AD7 Granted
Cavendish Court 11 - 15 Wigmore Street London W1U 1PF
Display for a temporary period of six months of a non-illuminated 'to let' board located on the face of the building at a height of between 3m and 4.6m above pavement level and measuring 1.2m x 0.9m.
-
26/03778/ADFULL Awaiting decision
318 Oxford Street London W1C 1BH
Details of a supplementary acoustic report; pursuant to condition 12 of planning permission dated 25th January 2022 (21/01633/FULL)
-
26/00379/ADV Awaiting decision
318 Oxford Street London W1C 1BH
Display of double-sided LED advertisement screen, measuring 1338 x 2100 x 245mm
Other full applications applications
In Westminster
-
26/04824/ADFULL Granted
New Zealand House 80 Haymarket London SW1Y 4TE
Detailed design and specification of new blinds to NZH based on mock-up trials on-site. pursuant to condition 32 (i) of planning permission dated 8th April 2024 (23/00571/FULL).
-
26/04829/ADFULL Granted
New Zealand House 80 Haymarket London SW1Y 4TE
Details of external and internal signage strategy pursuant to Condition 33(E) of planning permission dated 8th April 2024 (RN: 23/00571/FULL)
-
26/04841/ADFULL Granted
29 Henstridge Place London NW8 6QD
Details of the facing materials you will use, including glazing, and elevations and roof plans annotated to show where the materials are to be located pursuant to condition 5 of planning permission dated 18th November 2025 (RN:25/06159).
-
26/04989/FULL Awaiting decision
1 Kildare Terrace London W2 5JT
Erection of a mansard roof extending over the main house and side wing, replacement lower ground rear extension with roof terrace above, lowering of lower ground floor slab, installation of an air source heat pump in rear garden, new front boundary treatment, and new second floor window on the north elevation.
-
26/04986/FULL Awaiting decision
Inver Court Inverness Terrace London W2 6JB
Replacement of combustible materials in the render facades; timber decking and plastic soffits/ fascias to terraces with non-combustible materials on the 5th and 6th floors.