The practice has already worked on Lasdun's famous University of East Anglia and has now been asked to prepare a 10-year masterplan for the Grade II*-listed 1976 building in Bedford Way.
The SEH design team, which includes structural engineer WhitbyBird and service engineer Atelier Ten, was picked ahead of John McAslan + Partners, Wilkinson Eyre and Avanti to land the £5 million project.
Originally conceived in 1965 as a much larger 'urban megastructure', similar to the neighbouring Brunswick Centre, the institute building is surrounded by listed Georgian buildings.
Lasdun had initially drawn up proposals for five 'stepped spurs'; however only one was ever built.
Pevsner describes the building as 'highly effective visually, with a strikingly sculptural silhouette of angular concrete escape stairs rising above the floor.
'The layering and stepping, the pedestrian routes at different heights, and the use of a long single range tying all together can be traced back to Lasdun's earlier buildings, especially the University of East Anglia.'
Exact details of SEH's proposals remain firmly under wraps.