As it is so unusual it has meant the coin has been dubbed the "holy grail" of change collecting making it much sought after. The 20p coin was highlighted on Instagram by Coin Collecting Wizard.

A RARE 20p coin with a tiny error has just sold for over 230 times its face value – and you could have one sitting in your change without even knowing. An undated ...

"This issue impacted less than 250,000 coins out of the 136 million 20p pieces minted in 2008 and was a result of pairing the ...