Prof Barnes is a neurologist and has been involved in cannabis for the last 20 years – initially with GW Pharma for the development of Sativex. In recent years, he produced a report for the UK parliament on the efficacy and safety of cannabis and then obtained the first UK prescription for cannabis for the child Alfie Dingley. He set up the first cannabis clinic in the UK and the first teaching programme . He established the Medical Cannabis Clinicians Society and more recently the UK Cannabis Industry Council. He runs a consultancy, Maple Tree Medical Cannabis Consultancy, with Hannah Deacon, the mother of Alfie Dingley and the UK’s foremost campaigner.