Safely guarded in an air-conditioned vault in Atlanta, Georgia, lies one of western society's most valuable artefacts.

So valuable, that its owner could lose millions if anyone so much as got a look at it.

That's what Coca-Cola would have us believe anyway, claiming the only original copy of the soft drink's top-secret recipe lies underneath its US headquarters.

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But one man is threatening to lift this veil of secrecy this week as he claims to publish a copy of the original formula in a new book.

Historian Mark Pendergrast says the recipe was handed down through the family of Frank Robinson, the commercial partner of chemist John Pemberton, who first produced the drink in the summer of 1886.

In the third edition of his book, For God, Country and Coca-Cola: The Definitive History of the Great American Soft Drink and the Company That Makes It, Pendergrast reproduces what he claims to be the same recipe that Pemberton devised over 125 years ago.

Among the ingredients in the book are sugar, lime juice, nutmeg and coriander.

Pendergrast first came across the recipe when researching his first edition of the book, via Frank Robinson II, the great-grandson of the original Frank Robinson, though Robinson Jnr refused to show it to him.

After a legal battle over the ownership of the formula during Robinson Jnr's divorce, it eventually went to his sister laura Robinson-Vanwagner when he died, who passed a photocopy on to the historian.

While working as Pemberton's partner, Frank Robinson came up with the drink's name and the label's distinctive italic script, according to Pendergrast.

“Pemberton screwed Robinson by patenting Coca-Cola and saying that Robinson had no right to it,” Pendergrast told The Times. He claims that Pemberton then made his own copy of the recipe in an attempt to attract another buyer.

Changes have been made since the original recipe was written down. In 1903, traces of cocaine were removed after the drink became more widely available.

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Coincidentally, as Pendergast publishes the new edition, another American man claiming to have his own copy of a later verision of the recipe tried to sell it online for $5 million (£3.27m).

Cliff Kluge, an antiques dealer from Georgia, told ABC news that he had found a 1943 variation in an old box of letter that he'd bought at an estate sale.

Kluge opened the bidding for the recipe on eBay at $5 million but let users 'buy it now' for a staggering $15 million, claiming this would be a "drop in the bucket" if the recipe was to reproduce the drink.

Unfortunately for Kluge, the auction ended on May 14 and received no bids.

Coca-Cola has refuted both Pendergrast and Kluge's claims, insisting there is only one real copy of the recipe - tucked away in a vault in Atlanta.