Delancey is planning to submit a planning application to the Council for the demolition of the three existing office buildings on the site at Park Street and the construction of four new buildings providing up to 39,552 square metres of floorspace.
The new buildings, which would reach up to 79.90 metres, would provide 20,984 sq m of flats and 7,965 sq m of offices as well as shops, storage space and a spa.
The site is the former head quarters of National Grid and was bought by Delancey in August last year.