Located in the St James’s Conservation Area, the new seven-storey property has been designed as a 21st-century interpretation of a traditional Mayfair home. Its black brick frontage is inspired from the number ten Downing Street. The crafted metalwork, a major design feature of the building’s street presence, along with contemporary versions of gaslights on either side of the entrance door, recalls the glamour of a grand late Victorian or arts and crafts Mayfair home.

The project will be developed by demolishing the existing purpose-built 1960s office. The site is constrained by a seven-storey back wall to the southern aspect backing onto Blue Ball Yard. To overcome this challenge, the project will include a new four-storey green wall, which will improve the rear outlook and soften the existing wall’s impact with a recessed and lit stone panel at first floor level, directly facing a sliding wall and terrace for added light.

Apart from that it will also feature a rear profile which pulls away from the wall and steps in from the embassy building next door, with a rolling curved roof providing a glass curtain wall to help bring as much natural light as possible into the building, along with additional roof lights and recesses.

The design also includes a huge, double-storey contemporary version of an oriel bay window at the first and second floor levels, partly-fronted by a delicate metalwork screen both for privacy and added decorative value. Besides that the street level railings, porch grille and entrance gate will also feature antique bronze and brass with black iron uprights, whilst contemporary versions of gaslights will sit to either side of the glass entrance door.

The dark materials palette for the scheme includes Fairface black bricks with charcoal pointing; polished granite for the oriel window bay; polished granite for the window portals and frames with just the reveal in polished granite for the third floor windows, and charcoal black zinc for the standing seam roof. Reminding Victorian rusticated entrance levels, the whole ground floor level is made of flamed-finish granite with bands and recesses.

The interior layout includes a lobby, formal dining room, prep kitchen, receiving room/study, toilets, cloakroom, staircase and lift at ground floor level. The first floor features a formal reception room, family room, family kitchen, toilet, lift, stair, and rear terraced area.

On the second floor is the master suite with dressing rooms, wardrobes, bath and shower rooms, lift and stair, whilst the third floor comprises two further en suite bedrooms, linen and dressing rooms, with one of the bedrooms taking the form of a duplex space with sitting area and study space.

The fourth floor features the mezzanine level of bedroom three and a fourth en suite bedroom, along with the lift fore and an air-conditioning condenser room. Below ground, a new triple basement includes a prep kitchen, laundry utilities and plant rooms, and a staff suite.

The minus two level features leisure facilities, which include a pool, spa and deck; lobby and changing rooms; steam and sauna rooms and a changing area with toilets and showers. A media room with popcorn and drinks machines and plant/service areas are proposed at minus three level.

Apart from that the scheme also includes a lift through all levels, a dramatic internal stair from ground to fourth floor levels and an external stair leading from the ground to the lower ground levels at the front of the property.

The project is due to go on site in January 2014 for completion in the second half of 2015.