Leslie King spent nearly thirty years in the Forensic Science Service (FSS). His responsibilities included examining items submitted for the analysis of alcohol, drugs and other substances in cases of suspected fatal poisonings or those involving offences under the Misuse of Drugs Act or the Road Traffic Act. As a result, he has given evidence in the Criminal and Coroners” Courts as an expert witness on many occasions. Before retiring from the FSS in 2001, he was Head of the Drugs Intelligence Unit for ten years. In that role he was responsible for maintaining a UK drug seizure database, providing technical advice on the chemistry and legislation of drugs and their precursors to law enforcement agencies, forensic scientists and UK Government as well as international organisations such as the United Nations Office on Drugs and Crime and the European Commission. Before joining the FSS, Leslie King spent eight years in the pharmaceutical industry both in the UK and in Germany. At Loughborough University he carried out research on the analysis of barbiturates and on fluorescence and phosphorescence spectroscopy leading to MSc and Ph D degrees. Leslie King is a member of the Home Office Advisory Council on the Misuse of Drugs, and author/co-author of over eighty papers on analytical chemistry, spectroscopy, toxicology, risk assessment, forensic science and the epidemiology of drug abuse and is also a member of the Editorial Board of “Substance Use and Misuse”. He continues to work part-time as an advisor to the Department of Health and the European Monitoring Centre for Drugs and Drug Addiction on matters concerning synthetic drugs and risk assessments, as well as providing training to newer Member States of the EU on drug legislation and chemistry.