In this second of a series of three articles, attention is devoted to the developing role of psychiatrists and psychologists as expert witnesses. As far as psychiatry is concerned, the first recorded use of psychiatric evidence in an English court dates back to the first half of the eighteenth century, but it was not until the nineteenth century that psychiatry was recognized as a field that could contribute significantly to the law. Developments in South Africa regarding forensic psychiatry followed a similar pattern. As for psychology, immediately after its emergence as an autonomous science late in the nineteenth century, it interacted with law. Developments from the stormy early years to the present in the United Kingdom are discussed.