The traditional institutional models relating expert knowledge to social need are increasingly unable to cope with the demands of a technologically complex world. The knowledge needed to understand such a system is context dependent. It can no longer be assumed that there are general truths which have the same standing as physical laws. Although consultancy is often seen as a means of funding research, it is in fact an essential part of an academic's professional job and the knowledge thus gained is of vital importance to the needs of modern society.