Professor David Nutt is an expert on drugs, and how they work on the brain. He trained as a psychiatrist, and for almost 50 years his research has focused on new drug treatments for anxiety, depression and addiction. In the late 1980s, at Bristol University, he set up the first unit in Britain to bridge psychiatry and pharmacology. He’s now at Imperial College, where he is Professor of Neuro-psychopharmacology. He has published hundreds of scientific papers and 27 books.

All of this makes David Nutt sound like a pillar of the establishment. But the reason most people know his name is that he has repeatedly challenged the government over its policies on illegal drugs and alcohol, arguing, for instance, that it’s more risky to go horse-riding than to take ecstasy. In his words: “no one in a position of authority dares to speak the truth”. But he also stresses “I have repeatedly said that cannabis is not safe”.

In conversation with Michael Berkeley, David Nutt looks back on the childhood that gave him the confidence to challenge established opinion. Living on a council estate, he felt out of place at Bristol Grammar School, and was a very anxious child who couldn’t sleep. At night he used to creep to the stairs to hear the Proms drifting up from his father’s radio. Professor Nutt describes fascinating new research into treating depression using the active ingredient of magic mushrooms, and he reveals which music he plays to his patients during these experiments.

Music choices include Faure, Nielsen, Grieg and Beethoven – his Seventh Symphony, which David persuaded the crowd to dance to at a New Year’s Eve party. That experiment, he says, was a resounding success.

A Loftus Media production for BBC Radio 3 Produced by Elizabeth Burke