In July 1920, when the first Dangerous Drugs Act was passed, the UK drug scene was limited to small groups of Soho night people, smoking opium and sniffing coke and some middle and upper class people (mainly women) around the country quietly getting private morphine prescriptions from their GP ... Now, exactly 100 years on, we have hundreds of thousands of people using a whole smorgasbord of different drugs. How did that happen?The nineteenth century...