A letter up for auction at Sotheby's in London shows an 18th-century Irish wine merchant duped the British authorities in Dublin Castle by giving them "vile plonk" instead of high-quality Burgundy.

The letter, which is written by an archbishop to the secretary of a lord lieutenant, is part of a collection of correspondence which reveals what the British administration came up against while trying to govern Ireland.

According to the Irish Times, in the summer of 1751, Dublin officials were preparing for the arrival from London of Lionel Cranfield Sackville, the duke of Dorset and the newly-appointed lord lieutenant of Ireland.

The Church of Ireland Archbishop of Armagh, George Stone, was sent to check out the “lodgings” in Dublin Castle for the duke and the wine cellar.

Stone arranged a wine tasting and  discovered that the castle had been duped by a dodgy merchant. The wine supplied was “a vile infamous mixture” and “fundamentally bad."  The archbishop determined that the castle had been “scandalously abused."

Stone described the contents of bottles “sealed with black wax, and falsely and impudently called Vin de Beaune” as “the worst, and is, indeed, as bad as the worst tavern could afford."

He discovered that “the four barrels of Burgundy are almost equally bad” and was “sure that no person will ever drink a second glass of either”.

He wasn't the only one who tasted the wine. He invited a select group of “eight or nine” to the tasting which turned into a “melancholy operation."

The archbishop wrote to the lord lieutenant’s secretary to tell “his grace” the “disagreeable news."

He said: “I am very apt to conclude the whole business has been dishonestly transacted. I am confident that not a drop of the wine, so-called, was ever in the province of Burgundy”.

The name of the fraudulent Dublin wine merchant who concocted the fraud was not recorded.

The letters will be sold in an auction of rare books and manuscripts at Sotheby’s on July 10th.