A mistake made during the minting process can make a coin incredibly valuable, and it's still possible to find some of these ...

A 'rare' 20p coin has sold for almost 200 times its shop value because of one subtle error. What's more, the Royal Mint suggest more are still to be found. The 2008 ...

Coins that have mistakes or unusual features can sometimes turn into highly valuable treasures. Over the years, I've come across stories of collectors who discovered ...