Bovis signs agreement for Portman Square office retrofit
Bovis is working with BGO on a project to create 150,000 sq ft of sustainable space
24 September 2025
Bovis has entered into a pre-construction services agreement (PCSA) with BentallGreenOak (BGO) to deliver a comprehensive retrofit of 43–45 Portman Square, creating over 150,000 sq ft of sustainable office and retail space in central London.
The project, commissioned by BGO on behalf of the Welput Fund, will transform the existing office complex through a retrofit-first approach that retains much of the building’s original structure and historic façades. The scheme will remove one office floor to accommodate the addition of three new floors, increasing overall capacity while reducing carbon impact compared to a full redevelopment.
Plans submitted by architects Henning Larsen include the creation of a new roof garden designed to extend the adjacent Portman Square green space. The garden will incorporate biodiversity features such as bird houses and a rainwater retention system, and will contribute to the “Wild West End” strategy promoting urban greening across the district. Outdoor terraces, a pavilion, and landscaped areas are also planned to encourage social and collaborative use.
A key part of the scheme will see improvements made to the building’s large central atrium. Several floors of the eight-storey void will be infilled to increase office space, with a new layout introduced to improve circulation and connectivity within the building.
The retrofit will deliver fully electric operations powered by renewable energy, with energy intensity projected to fall by up to 72% compared with current performance. The building is being designed to achieve net-zero operational carbon and includes new windows to improve thermal performance, additional bicycle parking, and a comprehensive refurbishment of the interior office spaces.
The mansard-style roof extension will replicate the pitch and form of the existing roof, maintaining the building’s architectural character. Retail spaces at ground level will also be upgraded as part of the wider redevelopment.
On completion, 43–45 Portman Square will provide what developers describe as “future-proofed” Grade A office space with high sustainability credentials, enhanced amenities, and an improved connection to the surrounding urban environment.