The historic former headquarters of MI5 in London's exclusive Mayfair district could be transformed into a luxury private members' club and workspace, complete with a high-end Japanese restaurant, under ambitious new plans submitted to Westminster City Council.
From Spy Centre to Business Hub
Leconfield House Ltd, which has owned the prestigious Central London building for two decades, has submitted a licensing application that would see the basement, ground floor and rooftop terrace converted into premium dining and networking facilities. The company states this proposal would bring the property back into full use, creating what they describe as a "vital business hub within the Mayfair community."
Exclusive Amenities for Distinguished Clientele
The plans outline a sophisticated offering designed to attract what the owners call "the world's most distinguished individuals." This would include:
- A signature Japanese restaurant called Roof Shori on the rooftop terrace
- An exclusive basement lounge for gatherings of up to 60 people
- 90,000 square feet of "exquisitely curated space" including intimate lounges and private rooms
- The largest boardroom in Mayfair
- Health and wellbeing consultation facilities
- Acoustically-sealed pods for private meetings
The company emphasises that access will be strictly limited to members and up to four of their guests, maintaining an exclusive atmosphere. They also note that the proposed entertainment areas constitute just 16% of the building's net internal floor space, with services being "clearly wholly ancillary to the office use."
Addressing the Post-Pandemic Business Landscape
According to the application documents, the transformation responds directly to significant shifts in the post-Covid business world. The owners observe that more companies are seeking flexible workspace solutions rather than committing to traditional office models.
"Leconfield hopes the changes will attract ex-pats who moved overseas back to London," the application states, "giving them space to network and work without having to invest in large and expensive office space."
Late-Night Operations Spark Local Concerns
While the application proposes keeping the basement, ground floor and rooftop areas open until 5am seven days a week, music, alcohol service and film screenings would cease at 1am. This has prompted significant objections from local residents concerned about potential noise disturbance.
One objector wrote: "Most of the development in Mayfair over a decade has been residential. It would be a disaster for the local community if alcohol consumers spill out of Leconfield House every night at 1am or later, singing and slamming car doors."
Residents from the adjacent Chesterfield House have formally objected on grounds of noise and disturbance, with some questioning the necessity of weekend operations and late-night entertainment elements.
Assurances from the Developers
In response to these concerns, Leconfield House Ltd has provided several reassurances:
- The company states it has no intention of turning the property into a nightclub
- Any music played would be "appropriate to the main business use" of the building
- Food and drink service on the terrace will cease at 11pm
- Smoking outside after 11pm will be limited to 10 people under staff supervision
The company maintains that the proposal represents a balanced approach to bringing a historic building back to full use while respecting its Mayfair context.
Historic Building with Intelligence Heritage
Leconfield House boasts a remarkable history, having been constructed in 1939 and reconstructed in the 1950s. Most notably, it served as the headquarters of MI5, the United Kingdom's domestic counter-intelligence and security agency, until the mid-1970s.
Currently, the building is partially let as traditional office space to select tenants, but the new proposal would mark its most significant transformation in decades.
Westminster City Council is scheduled to review the comprehensive licensing application on Thursday, January 29, 2026, with the decision likely to set an important precedent for similar developments in London's most exclusive districts.
