The scheme, which is being developed with PRP Architects, includes proposals to convert the existing Oaklands College buildings into 40 flats and build another 277 apartments in the surrounding parkland campus.
Submitted for planning in December 2004 (AJ 27.01.05), the architects had originally hoped they would be able to start work on the site last summer.
However, the local authority was always opposed to the controversial proposals to overhaul the complex, built in 1960 to the designs of John Wakely, from Hertfordshire County Architects' Department.
Today the majority of the buildings stand empty because the college has moved most of its facilities to another site in the town.
Pardey's plans include rebuilding the school's original entrance canopy and reflecting pool - both removed years ago - and renovating the external walkways between the blocks.
The public inquiry is due to start on 27 February.