From Goldfinger (the book, not the movie – duh):
A big man in Mexico had some poppy fields. The flowers were not for decoration. They were broken down for opium which was sold quickly and comparatively cheaply by the waiters at a small café in Mexico City called the ‘Madre de Cacao’. The Madre de Cacao had plenty of protection. If you needed opium you walked in and ordered what you wanted with your drink. You paid for your drink at the caisse and the man at the caisse told you how many noughts to add to your bill. It was an orderly commerce of no concern to anyone outside Mexico. Then, far away in England, the Government, urged on by the United Nations’ drive against drug smuggling, announced that heroin would be banned in Britain.
There was alarm in Soho and also among respectable doctors who wanted to save their patients agony. Prohibition is the trigger of crime. Very soon the routine smuggling channels from China, Turkey and Italy were run almost dry by the illicit stock-piling in England.
Though it’s off-topic, I can’t resist adding the following, rather less insightful passage from the same chapter:
James Bond, with two double bourbons inside him, sat in the final departure lounge of Miami Airport and thought about life and death. … He stubbed out the butt of his cigarette and sat, his chin resting on his left hand, and gazed moodily across the twinkling tarmac to where the last half of the sun was slipping gloriously into the Gulf.
James Bond must have unusual eyesight to be able to see the Gulf of Mexico from Miami.