THE OWNERS of a rare 20p coin with a Royal Mint error could make a huge profit on the buying and selling site eBay.

One seller has recently sold his coin, dubbed the 'holy grail of change collecting' by The Britannia Coin Company of Royal Wootton Bassett, for £70 - 350 times its face value.

Twenty pence pieces were struck without the year by The Royal Mint in November 2008. 

The seller describes the coin as: "This rare 20p coin from the British Decimal Coinage is a must-have for any serious collector. The shield design on the obverse side is beautifully crafted and the absence of a date makes it a unique addition to any collection.

"This particular coin has been graded and slabbed by CGS, ensuring its authenticity and quality.

"The denomination of this coin is 20p and it was minted in 2008.

"It is a great addition to any collection of British coins, especially for those interested in the history of British currency.

"Don't miss out on the opportunity to add this rare and unique coin to your collection."

The Mint reports that of the 136 million twenty pence pieces minted that month, only about 250,000 coins were minted with this unique error.