According to the auctioneers, the egg, known as Cuckoo Cuckoo, was uncovered by Clive Pinder, from Dorset, at Cricket St Thomas in Somerset in 1983.
He sold the egg at auction for £6,500 in 2017, before the next buyer put it up for sale with the auction house.
The result set a new auction house record for Batemans and a new world auction record for any Cadbury’s Conundrum egg, the auctioneers said.
Batemans previously sold the secret thirteenth 22-carat gold egg twice, first in July 2017 for a hammer price of £17,200 and again in February 2021 for £31,000.
“The Conundrum eggs are a fascinating piece of British cultural history,” Bateman said.
He described the advertising campaign as “one of the most memorable” of his time, and said the hunt captured “the imagination of millions”.
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