At the heart of the 26.5ha brownfield development, which goes in for planning in July, is a 510-bed hospital for West Hertfordshire NHS Trust and the redevelopment of Watford FC's Vicarage Road ground.
Now, guided by Watford Borough Council, that scheme, several smaller health care packages, and the redevelopment of the stadium have all been pooled into one massive masterplan.
Benson & Forsyth director Alan Forsyth explained that the topography of the west Watford site - which is situated on a steep slope cut off from the town centre by a river - had previously stifled development.
Forsyth said: 'The site has been a mess, a patchwork of unsuitable places.'
He added that under Benson and Forsyth's masterplan, which 'knitted a hospital into the urban fabric', the slope would be cut into to provide hospital parking, leaving open spaces 'for public enjoyment'.
The project is being backed by West Hertfordshire Hospitals NHS Trust, Watford FC and Watford Borough Council as well as the East of England Development Agency.
Completion of the entire scheme is scheduled for late 2016.