Orion Capital Managers has started the speculative redevelopment of BT’s former City of London HQ, in one of the largest redevelopments in London’s history.

Orion said this week it had appointed Mace as the main contractor to undertake a £160M redevelopment of the building, to be renamed Panorama St Paul’s. Orion and Mace have flagged how much carbon it is saving by redeveloping rather than knocking the building down and building a new one. And by starting the construction without a tenant in place, Orion is putting its money on the fact companies will still want to take office space in city centres at good rents.

Orion paid £209M for the building, now vacated by BT, in 2021, putting its total outlay on the scheme at around £370M. The firm, run by Aref Lahham, Van Stults and Bruce Bossom, is one of the oldest independent opportunity fund managers in Europe, having been founded in 1999.

The redevelopment will see three storeys added to the existing 10-storey building, and the total lettable space increased from 517K SF to 807K SF. In addition to offices, the building will offer a retail arcade at street level, a rooftop terrace with a restaurant and a wildflower meadow that will be open to the public.

Compared to a full demolition and rebuild, working with the existing structure cuts the carbon footprint in half, Mace said. Consequently, retaining the core structure achieves carbon savings of 465kgCO2 per square metre. In addition, by adopting a circular economy approach, much of the existing building material will be recycled, with more than 1,500 tonnes of Portland stone and granite set to be redesigned and reused.

Since pre-construction works began March 2021, Mace worked closely with the architects Kohn Pedersen Fox Associates to save 296 tonnes of carbon by replacing the concrete piles with a more environmentally friendly steel pile solution, the contractor said.

The redevelopment is targeting a BREEAM Outstanding certification for the offices, WiredScore Platinum and NABERS 5* Excellent rating.

Completion of Panorama St Paul’s is expected in 2025.

“It is now critical to align the environmental and social values of occupiers to that of the workspace they occupy and with Panorama St Paul’s, we believe that this is a new and relevant addition to the London office landscape that genuinely delivers,” Orion founding partner and Managing Director Aref Lahham said. “It will be a building that cares, for occupiers for whom sustainability, the environment and the health of their staff are priorities.”