Hidden inside Dr Jekyll and Mr Hyde is a story of hogwash, tax, a vicar, drunkenness and the Gin Epidemic of 18th Century England.

To understand this it's helpful to know a little of the history of English gin and two distantly related men, the Reverend Walter Jekyll and Sir Joseph Jekyll.

The story of English gin begins in the late 1600s when mildewy, rotten English wheat and barley was fed to pigs as hogwash because bakers and brewers (beer makers) couldn't use the grain.

Then, in about 1690, some imaginative English distillers decided to use this hogwash to make a truly awful spirit which would go on to become one of the world's first alcopops. This foul spirit was English gin. And although disgusting  its production opened the door to the English Gin Craze of the 1700s and drunken social disorder.

All of this began with the English taste for Dutch gin.

Dutch gin had been seeping into England since the rule of William of Orange in the late 1600s. The problem was it cost too much for most people. This was because hefty taxes had been placed on Dutch gin to help pay for William's war against France.

Yet despite the high cost of Dutch gin many English developed a taste for the spirit. Small doses of gin, unlike beer, caused quick intoxication. What's more gin could be hidden in cupboards, then secretly brought out and gulped down.

English distillers therefore recognised a market for cheap gin. So, from about 1690, English hogwash gin (which was only vaguely like Dutch gin)  was made and sold by malt distillers.

Then in about 1720, English compound distillers recognised an opportunity and entered the gin business. They started to mix the hogwash malt gin with additives to mask the offensive taste. Seasonal fruits, sugar and anything which might make the gin more drinkable, marketable and saleable were added.

These compound distillers sold the 18th century gin alcopop to masses of unlicensed gin peddlars and merchants. Men and women, young and old, the poor and not so poor all bought the compound distiller's gin and went into business. Many also mixed the alcopop gin with water (to increase profits) then sold it to their neighbours, friends, relatives and passerbys.

This marked the beginning of the Gin Craze. The compound distiller's alcopop saw gin sales leap, particularly in London. Consumption of spirits doubled. By 1729 the spirit consumption had doubled again. It was to keep soaring up until 1751. And by the far the most popular and cheapest spirit was gin. By the 1740s English consumption of spirits had risen by over 700 percent compared to that in 1700.

But it wasn't as if the English, in particular the Londoners had given up drinking beer. Remarkably the amount of beer consumed by the average English person remained the same throughout the Gin Epidemic (1720-1751). What happened  was more people began to drink alcohol. And unfortunately many of these new drinkers were women, particularly poorer women.  Mothers, grandmothers, single women and pregnant women all fell victim to gin; sometimes neglecting their own health and their children's health. A generation of children were blighted by Fetal Alcohol Sydrome. (Physical and mental damage caused by drinking alcohol during pregnancy.)

While the landed gentry and distillers were delighted with how the gin craze had created a thirsty market for grains and malt spirits some in government and the community were less delighted. England needed strong soldiers, healthy merchant sailors and reliable laborers. Gin, on the other hand,  was inflating crime and giving birth to a frail, dull, sickly generation of men and women. Something had to be done....

So what's this got to do with the story of Dr Jekyll and Mr Hyde published in 1886, over 150 years later?

Robert Louis Stevenson, the story's author, was a dipsomaniac. That is an alcoholic with a dreaded craving for alcohol. He admitted as much to his friend Sidney Colvin.

His classic Victorian horror story Dr Jekyll and Mr Hyde was written in England during the anti-alcohol or Temperance Movement of the 1800s.

In the story the respectable Dr Jekyll becomes smitten by a potion he manufactures in his laboratory. The potion causes him to turn into the monstrous Mr Hyde, Jekyll's evil alter ego.

Stevenson wrote the story in the midst not only of the Temperance Movement but also during a time when wealthy men frequently enjoyed having their own private laboratories.

A private laboratory was a sign of affluence, leisure and education. As the understanding of organic chemistry and atoms grew so too did the number of private laboratories. These sprung up in well-to-do homes across Europe, North America and the English speaking world. A house with a laboratory was a little like owning a luxury car, a cinema or a boat today.

At the same time, a growing interest in the mind and psychiatry, combined with the mental misery of the Industrial Revolution, saw an increase in "lunatic asylums" and studies on the cause and treatment of madness.

So this was the society in which the dipsomaniac, often drunk Stevenson lived; a society aware of science, madness and the curse of alcohol. It's not surprising therefore his character Jekyll is a respectable doctor who tinkers away in a laboratory and secretly drinks potions which release his evil alter ego.

At the time of writing his horror story, one of Stevenson's best friends was the Anglican clergyman Reverend Walter Jekyll. Stevenson was sufficiently impressed by Rev Jekyll's decency that he used his friend's name for the fictitious, respectable characater Dr Jekyll.

Yet Dr Jekyll was a fatally flawed character, addicted to a potion and the evil transformation it caused.

At first glance it would seem Rev Walter Jekyll might have reason to be offended by Stevenson's use of his name. So was there another reason why Stevenson used the uncommon English name "Jekyll"?

It appears there was. The story of Dr Jekyll and Mr Hyde is an allegory to the curse of alcholism and English attempts to control it.

One man famous for his attempts to control alcohol was Sir Joseph Jekyll, who lived during the Gin Craze. Sir Joseph  was a legendary politician, barrister and judge who loathed drunkenness, in particular the unlicensed sale of gin. He was obsessed by a desire to control it and consequently introduced the Gin Act of 1736 which placed a huge tax on gin sales. This Act  caused public riots, but laid the foundations for the GIn Act of 1751 which banned the sale of gin by unlicensed peddlars and merchants.

Over one hundred years later Sir Joseph Jekyll's disgust for gin helped inspire and guide the Temperance Movement. It was certainly a name very familiar to Robert Louis Stevenson. But more than that, the ghostly presence of Sir Joseph Jekyll  haunted the dipsomaniac Stevenson. That was because his very good friend the Reverend Walter Jekyll was a descendant of the legendary anti-drunkenness crusader..

The transforming draught: Jekyll and Hyde, Robert Louis Stevenson and the Victorian alcohol debate; Thomas L. Reed; McFarland and Co; North Carolina and London; 2006

Vailima Letters: Being Correspondence addressed by Robert Louis Stevenson to Sidney Colvin, November 1890-October 1894, Methuen; London; 1895.

Craze. Gin and Debauchery in an Age of Reason; Jessica Warner; Profile Books; London; 2003

Sir William Hogarth, Prints and Drawings (1720-60) Including Beer Street and Gin Lane (1751)