The work of ‘experts’ with policy advisory panels plays an important part in the making of illicit drug and other policies. This article explores what is involved in this work. It uses critical realist auto-ethnography of the author’s experience over five years of working with the UK’s Advisory Council on the Misuse of Drugs and the House of Commons Health and Social Care Committee. It analyses: how some people become recognised as a ‘suitable’ expert through relational networks of esteem, while others are excluded; how bureaucratic processes and scientific modes of discourse select some types of information rather than others for the creation of acceptable evidence; and how agenda-setting and self-censorship can reinforce the exclusion of other knowledges, further narrowing the range of people and ideas that shape evidence for policy.