The enormous success of Robin Birley’s 5 Hertford Street Private Member’s Club, which opened in 2012, became the most sought after membership club in the world. Within the first 3 years of opening, Robin Birley realised the success of the club was limited by its size. Robin Birley having developed the Grade II listed building at levels basement, ground and first floor, decided to take on the upper floors, second and third. Robin Birley being aware of Blair Associates Architecture Ltd success in major schemes across Westminster chose to commission Blair Associates Architecture Ltd to convert upper storeys into additional club space. This was a complicated commission involving construction over the ultra high quality club. Blair Associates Architecture Ltd developed with Robin Birley a three dimensional layout of the club upper storeys which involved substantial alteration to the roof structure, the listed building, creation of a new roof terrace, re-establishing working fireplaces and relocating the entire primary plant from the first floor to the new roof storey. Blair Associates Architecture Ltd won planning and listed building consent and co-coordinating architecture, structure and MEPH new kitchens, powder rooms, lounges and restaurants. The design was meticulously thought through before starting the complicated process of construction without impacting the fully operational club below. The scheme took 1 year to build, adding 850m² to the club. Construction through careful consideration and design proceeded on program and on budget, providing hugely successful space not only for front of house operations but also back of house.