It was a Friday afternoon, April 16, 1943, in the laboratories of one of Basel’s major pharmaceutical companies, Sandoz. The 37-year-old Dr Albert Hofmann, who had worked for Sandoz for fourteen years, was doing research into the various properties of rye fungus, in a search for a cure for migraine. During the afternoon he began to feel peculiar, and went home to lie down. “With eyes closed,” he wrote, “I perceived an uninterrupted stream of fantastic pictures, extraordinary shapes with intense, kaleidoscopic play of colours.” Unwittingly, Dr Hofmann had taken the first-ever acid trip – he had synthesized lysergic acid diethylamide, or LSD, from the fungus and had absorbed the drug through his fingertips.

After the weekend, he decided to experiment on himself with more scientific precision, and so dosed himself with some more LSD. This time, though, his apprehension at exploring an untested area of pharmacology led to unforeseen paranoias. While cycling home, “a demon had invaded me,” he later wrote. Thinking that milk would act as an antidote to the drug, he knocked on his neighbour’s door to ask for some, only to discover that “she was no longer Mrs R., but rather a malevolent, insidious witch with a coloured mask.” He took to his bed, and woke up next morning exhilarated. “Breakfast tasted delicious and gave me extraordinary pleasure. When I later walked out into the garden, in which the sun shone after a spring rain, everything glistened and sparkled in a fresh light.”

Dr Hofmann continued his quiet work into the psychoactive properties of both LSD and other hallucinogens, such as magic mushrooms, in Basel while the drug itself – his so-called “problem child” – escaped the confines of the laboratory. A small band of writers were attracted to LSD as a way of unlocking the secrets of the mind: Aldous Huxley’s Doors of Perception (1954) is probably the most famous creative work to stem from experiments with mescalin, an LSD derivative. Underground tests on volunteers by the British and American military were so dramatic that subsequent top secret reports suggested that if LSD could be deployed in a missile fired at the Soviet Union, it could at a stroke put the entire Red Army out of action. The drug hit the headlines through its role at the core of the 1960s hippy counterculture: the turmoil it appeared to be causing to US society, with teenagers dropping out of college and discovering alternative lifestyles, unnerved the establishment to such an extent that the US Congress passed a bill criminalizing LSD in 1966. Worldwide governments followed suit shortly afterwards. In the late 1980s and 1990s, illegality notwithstanding, a whole new generation of partygoers rediscovered LSD, on a wave which popularized a variant hallucinogen, Ecstasy, and gave rise to “club culture”.

Massive controversy persists as to the medical uses of LSD and hallucinogens in general (such as cannabis) – but any meaningful research is hampered by the drug’s continuing outlawed status. Dr Hofmann himself, in an interview given in 1993 at the age of 87 to the British Independent newspaper, said: “LSD is not addictive, it is not toxic. The danger with LSD is this very deep change in consciousness: it can be beautiful, it can be terrifying. We have integrated alcohol and tobacco, but we’ve not integrated the hallucinogens. The next step is that it should be put into the hands of the psychiatrists. Fifty years’ experience is nothing. For a substance which exhibits such new and extraordinary properties you must have much longer. It should be possible to study this substance properly.”