Leconfield House

Mayfair W1J
Commercial development

Key Details

Curzon Street, London W1J 5JA
Local Area
Local Authority
City of Westminster
Greater London


Leconfield House is a proposed office building redevelopment on Curzon Street in Mayfair, London W1.

The new plans designed by EPR Architects see the reconfiguration and extension of Leconfield House.

The ground and first floors will be transformed to include restaurant space with a new stone facade on the ground floor.

The first basement level will house a health club and spa, while levels 2 and 3 will feature a health and diagnostic center with treatment, diagnostic, and doctor's rooms, as well as retail and food and beverage spaces.

Levels 4 and 5 will offer co-working spaces.

Levels 6 and 7 will be replaced with new rooftop levels featuring rooftop restaurants and terraces, and the rooftop will also host relocated plant equipment, screened from view from the street.

An additional basement level will be added for administration, staff areas, and mechanical plant spaces, including an improved sprinkler system.

Delivery arrangements will be enhanced by consolidating off-site deliveries to reduce the number of deliveries to the site.

Planning History
February 2020 - Planning application submitted for: Replacement of existing 7th floor level and erection of new 8th-floor roof extension and roof plant area, excavation of three new basement levels, infilling of windows at the rear, replacement windows and doors at ground and first floor level, new loading doors onto Chesterfield Gardens and refurbishment works, all for use of the building as a 60 to 70 bedroom hotel and private members' club including restaurants, spa/wellness centre and retail (sui generis use), with plant at 6th, 7th floor, roof level and basement level 3 and roof terraces at seventh floor level. Westminster council ref. no. 20/01200/FULL.


The existing 7-storey building was the headquarters of MI5 following the Second World War from 1945 until the mid-1970s.

Leconfield House is situated on a site that was once part of Chesterfield House - a Palladian mansion built from 1746-1752 for Philip Stanhope, the 4th Earl of Chesterfield. The house was designed by Isaac Ware. The building sat on the corner of South Audley Street and Curzon Street, facing the park. Demolished in 1934 and replaced by Chesterfield House and Leconfield House.

1. Lord Chesterfield and His World Front Cover Samuel Shellabager Biblo & Tannen Publishers, 1971;
2. Design & Access Statement by EPR architects 2020 for Westminster Council.

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