Renovation of Grade II* listed building for the Institute for Government, which was previously occupied by the Privy Council. The project included works to an existing ‘cantilevered’ stone staircase that had a wall beneath it. The removal of this wall to provide extra circulation space was to be justified by load testing as well as calculation. Another ‘cantilevered’ stone staircase required new holes to be cut for services risers. This was justified using finite element analysis. A new steel structure was constructed within the existing lightwell to provide a new meeting room.