Transformation of 1920’s London building moves ahead

Located in the heart of the Portman Estate Conservation Area, Portman Square connects the busy shopping district of Oxford Street and the surrounding residential area of the Portman Estate. The redevelopment honours the 1920s architectural heritage, while providing an active, healthy, and modern workplace for Londoners.

The retrofit is focused on creating an inviting ground floor, inclusive community spaces and a healthy outdoor environment. Once complete, the building will feature new, active and open façades, widening the entrance to allow a greater flow in the ground-floor commercial spaces. The interior will be reimagined with communal workspaces and an updated atrium. The existing roof will be extended upwards, adding further office space, outdoor terraces, and a biodiverse rooftop garden – designed to contribute to the ‘Wild West End’ strategy; a new corridor of connected green spaces in London’s West End.

Originally designed by Messrs Joseph architects in 1928, the building will be carefully repurposed through a series of considered, low-impact interventions that support long-term sustainability. Its historic façades will be retained, with new windows introduced to significantly improve thermal performance.

Inside, the previously dividing atrium will be reconfigured to create a more fluid, collaborative workspace. Several atrium floors will be infilled to expand usable area and encourage better flow throughout the building, with 65% made up of the existing, retained structure. Other upgrades include additional cycling amenities, biophilic design features to support local biodiversity, and a new rooftop pavilion set within a landscape of green clearings and shaded pockets – places to pause, connect and recharge.

The development continues in close collaboration with client BGO, on behalf of the Welput Fund, with project completion expected in late 2027.