> Read Doyle’s Sherlock Holmes short stories to see how drugs had permeated throughout British society… <
My favorite Sherlock Holmes actor was Jeremy Brett. In an episode that stuck with me, Watson walks into Holmes’ study unexpectedly. And Holmes quickly closes the top drawer of his desk.
We get a brief glimpse of a syringe.
You have ZERO idea what you are talking about. Cocaine, Sherlock Holmes' drug of choice, was not regulated anywhere in the US until after 1900, and not on the Federal level until about WWI, so the fact that it wasn't illegal in Britain in the 1800s is not even comment worthy.
And far from an attempt by dope fiends Brits, jonesing for a fix, to take opium from the Chinese, the Opium Wars were waged by Britain and France to keep the Chinese Government from interfering with exports of British and French opium to China. The (British Colonial) Government of India regulated opium production in an attempt to make sure it went to Chinese dope smokers, and was not smoked in India, and derived something like 1/6 of its total revenue from the opium trade.