Jack "Legs" Diamond, one of America’s most notorious bootleggers, walked into Berry Brothers & Rudd on London’s St James’s Street one day in 1920 and ordered several hundred cases of their best Scotch.
His request may have raised some eyebrows, given that the firm had been purveyors of wine and spirits to royalty and nobility for more than 300 years. But he wasn’t turned away.
New research by a Scottish author suggests that Berry Brothers & Rudd were secretly involved in smuggling Scotch whisky into the United States during the 13 years it was "dry".
George Rosie, author of Curious Scotland, Tales from a Hidden History, which chronicles the antics of the bootleggers, said the very profitable relationship between respectable whisky firms and American mobsters "is one of the great stories that has never been told".
In 1920, the United States was among the most lucrative markets for the whisky barons of Glasgow. So when Congress passed the Prohibition Act it became clear that for the whisky industry in Scotland to survive, the legislation would need to be circumvented.
Mr Rosie claims that Francis Berry, the junior partner at Berry Brothers & Rudd during the time of Prohibition, travelled to Nassau in the Bahamas, where he struck up a deal with a Scots-American seaman from Florida called Bill McCoy.
The deal was simple. Berry Brothers would legally ship their Cutty Sark Whisky into the British colonial government’s warehouses in the Bahamas. From there, the whisky would be uplifted by McCoy’s schooner and taken to the international waters off the New York/New Jersey coast.
Once there it would be sold to American gangsters such as Charles "Lucky" Luciano, "Bugsy" Siegal and "Nucky" Johnson, who used high-speed motor boats to smuggle Scotch on to the mainland, where it would be distributed among other organised gangsters, including Al Capone.
Mr Rosie said: "The arrangement worked well. The gangsters could not get enough of the product, Bill McCoy added to his substantial bank balance, the Berry Brothers’ distilleries in Scotland did brisk business, and the firm carved itself a niche in the American market which it was able to exploit when Prohibition ended in 1933."
Exports of whisky to the Bahamas rose astonishingly during the period - from 944 gallons in 1918 to more than 386,000 gallons in 1922. Smaller Scotch depots were also established in Havana, the Turks and Caycos Islands, and on Grand Cayman.
Mr Rosie said: "The Scotch whisky industry prior to Prohibition had gone through a long period of aggressive expansion and they were determined to keep hold of the American market by any means that they could.
"They regarded Prohibition as an inconvenient legality."
Ronnie Cox, a director with Berry Brothers & Rudd, said the relationship laid the foundations for Cutty Sark becoming the most popular whisky in the US.
He added: "Bill McCoy earned a reputation for providing liquor that was the real stuff ... in other words it was not diluted or adulterated, which most of the other whiskies were during the time of Prohibition.
"What he sold was the real stuff hence the term ‘the real McCoy’."
Scotland’s "war" with the US lasted almost 13 years, from early in 1920 when Prohibition was introduced until the end of 1933, when the act was repealed.
Charles Maclean, the author of Scotch Whisky: A Liquid History, said: "Prohibition was the best thing that ever happened to Scotch.
"By 1936, America had become the biggest export market, whereas before, Australia was the largest export market," he added.
"Essentially the Scotch whisky industry played it absolutely right and this was in the face of fierce criticism from the American government, who were complaining bitterly to the British government, who were pretending to do things but really not doing a lot. But Berry Brothers were just playing the same game as everybody else."