Costain will occupy the 7^th floor of 70 St Mary Axe as it increases its presence in the capital.

The move is expected to complete in the second half of 2024, ramping up the firm’s existing London capacity by around 400%.

Alex Vaughan, Costain’s chief executive, said: “This is an exciting new chapter in Costain’s 159-year history and one that points to a bright future.

“Over the last few years, working requirements have changed, with increased co-location with our customers and dynamic working.

“We need an office that makes it easier for our people, customers and partners to connect, collaborate and create, and our new head office will do just that.”

The new office was selected with sustainability in mind, with the building having the highest energy efficiency certification, including a BREEAM Excellent rating, and space for 328 bicycles.

As part of the move, Costain will vacate its existing Maidenhead and London offices. The company will maintain a presence in Maidenhead for staff based there and is finalising a suitable location.