The roles of Lord Foster and his senior partners David Nelson, Spencer de Grey and Graham Phillips will be largely unaffected by the restructure. However, it is thought that they will step back from working on specific projects in favour of acting as design reviewers.
Beneath them, the practice will be divided into six groups, each under the control of a director or project director. Building understands that these six groups will be headed by Grant Brooker, Nigel Dancey, Brandon Haw, Paul Kalkhoven, Mouzhan Majidi and Andrew Miller.
The groups will be divided according to staff expertise rather than along disciplinary or geographical lines. Haw, for example, has extensive experience of office developments in the USA, whereas Miller is an expert on East Asian work.
Shuttleworth left at the end of last year to form his own practice, Make. He has since been joined by former Foster colleagues John Prevc, Sean Affleck and Jason Parker.
A Foster and Partners' statement suggested that the restructuring was not linked to Shuttleworth's departure. It said: "The restructuring started more than two years ago. It is well advanced but is still evolving and will be fully finalised by the end of this year."
However, a source in the practice said the restructure would fill the void left by Shuttleworth's departure.
The source said: "The restructuring was spurred by Ken leaving, but it is a sensible way to run such a large office."
Another insider said it would reduce the tendency for cabals to form around the key design men.
He said: "There tended to be a situation where you were either 'David's boy' or 'Spencer's boy'.
Now they will have a more roving brief."
Four or five members of each of the sections will also form "design review" groups that will monitor the quality and progress of their section.