Then, just 11 days later, Hoffmann created another top-selling medicine. In trials, diacetylmorphine hydrochloride, or diamorphine, was said to make people feel like heroes. So Bayer named it heroin.

First produced some years earlier, when the British chemist C R Alder Wright tried boiling morphine, the active ingredient in opium, with a variety of acids, this “semi-synthetic opioid” shared the pain-relieving and euphoria-inducing properties of the opiate from which it derived.

But while it was found to be three times more powerful than its predecessor, it appeared to have one crucial advantage. Heroin, it seemed, was totally non-addictive.

Ironically, morphine, which was first isolated from opium by a German apothecary in 1805, was itself once marketed as a more powerful but non-addictive substitute for that ancient analgesic. But by 1866, when 45,000 returned home from the American Civil War addicted to it, morphine was regarded as a very mixed blessing indeed. Rich ladies in Britain frequently took a phial to society events, and it seemed that the antidote had become worse than the poison.

And so when, in 1898, Bayer began selling heroin as a non-addictive cure for morphine addiction, the drug was regarded in a similar light to aspirin - particularly as, in elixir form, it was found to inhibit childhood coughing.

It was more than a decade before the bad news arrived, but it proved somewhat embarrassing for Bayer. For research showed that, once inside the human body, all opium-like drugs, including heroin, are converted by the liver into the same chemical - morphine.

In 1914, the Harrison Narcotics Tax Act made it illegal to manufacture or possess diamorphine in the US. And while many countries, including Britain, allow its continued use as a pain-killer, it seems unlikely that heroin will ever again be spoken of in the same breath as aspirin.