A significant national programme on the development of advanced software for VLSI system design is reported. The Silicon Architectures Research Initiative (SARI) is supported by selected UK electronics companies as well as the UK Department of Trade & Industry (DTI). It has resulted in the design and development of an interactive software suite for optimising a system implementation in VLSI circuit form. The new software permits a specific system design to be optimised in terms of chip speed or area prior to interfacing with one of the available commercial silicon layout tools.