Colorado businessman Richard Gooding, who died in 2014 aged 67, amassed the collection over two decades, flying regularly to Scotland to visit auction houses and distilleries in a quest for some of the world's rarest single malts.

Perthshire-based Whisky Auctioneer will sell the individual bottles in the so called "perfect collection" of Scotch at two separate online auctions next year. The collection includes the world's most expensive whisky - a Macallan.

A single bottle of Fine and Rare Macallan from 1926 is expected to fetch up to 1.2 million pounds. A 1919 Springbank from the collection is valued at 180,000-220,000 pounds. A rare 1937 Glenfiddich is likely to sell for 60,000 pounds.

"Its sheer scale and rarity makes it one of the most exciting discoveries in the whisky world," Iain McClune, the founder of Whisky Auctioneer, said.

A bottle of Gooding's favourite Black Bowmore from 1964 has an estimated hammer price of up to 17,000 pounds. 

The collection includes bottlings from some of Scotland's lost distilleries, including Old Orkney from Stromness Distillery and Dallas Dhu.

"Collecting Scotch was one of Richard's greatest passions – an endeavour that spanned over two decades," said Gooding's wife, Nancy. "He loved every aspect of it; from researching the many single malt distilleries to visiting them and tasting their whiskies."

Gooding, who kept the collection at his own private pub at his home in the Unites States, owned the Pepsi Cola Bottling Company from 1979 until 1988, when he sold it to its parent company PepsiCo.

By Joanna Taylor