John Maynard Smith was one of Britain's most eminent evolutionary biologists. For over forty years, from 1954 onwards, he also regularly appeared on radio and television. He primarily acted as a scientific expert on biology, but in the late 1960s and the 1970s he often spoke on the implications of science for society. Through four case studies, this paper analyses Maynard Smith's scientific broadcasting against developments within the BBC as well as the relation between science and society in Britain. It (...) finds that while Maynard Smith acknowledged and accepted increasing mediation through the BBC and its producers, he stayed publicly and privately critical of both format and content decisions in his reflections on the science–media relationship. At the same time, we find that over a decade before the 1985 report by the Royal Society on the public understanding of science, Maynard Smith came to think of engagement with the public via the media as scientists’ responsibility. (shrink)