The Old Tom Gins were the natural successor to Jenever and the first Gins distilled in Britain. They were known as low quality distillations, masked with the addition of rose water, orange flower, elderflower or sugar. 
The Old Tom Gins were almost extinct but a new movement has brought them back into the spotlight. Maintaining their sweet flavour of the olden days, they are now high quality Gins and are much appreciated in cocktail mixing. 

Background
“Rome wasn’t built in a day”. Nor was Gin. During the 80 years war, British soldiers brought back Jenever. At the same time, a significant number of Flemish soldiers who fled the war, in the direction of England, began to distil their own. Homemade production saw a large increase during the reign of William of Orange. The kind liberalised distillation, making it possible for any citizen to distil his own spirit. Cumulatively, taxes were raised on imported drinks, and conditions were ripe for a boom in the production and consumption of Gin. 
Excessive consumption of alcohol, suddenly widespread, started to affect an England already with grave economic problems with a social crisis, a direct consequence of alcohol consumption, where infant mortality, drunkenness, work absenteeism and crime became common in quotidian England.
Seeking to diminish the consumption of Gin, the first Gin Act, 1736, was signed and brought in an annual tax of £50 was placed on producers of Gin. The measure was strongly contested and the population took to the streets, forcing a revision to the law. The Gin Act of 1751 took control of the whole business from production to distribution. The new law couldn’t diminish consumption and it merely went underground. There were many places where illegal Gin was sold, almost always with a black cat, Tom Cat, or Old Tom, marking the spot. Gin consumed at that time was of very low quality. It was common to use sweet ingredients to mask the quality, like elderflower which was abundant in England, or rose water. At worst, sugar was added to make it more drinkable. The designation Old Tom remained associated to low quality Gin and naturally died out once more controlled quality Gins, the London Dry Gins, became the norm. Today, however, there are several brands launching their own versions of Old Tom. They are now of unquestionable quality with a common trace of sweetness. For that reason, they are especially apt for use in cocktails, where less dilution in the Gin needs a some sweetness.