In 2008, to celebrate the 60th Birthday of Prince Charles, the Royal Mint released a very Limited Issue Prince Charles Piedfort £5 Five Pound Silver Proof Coin struck in solid .925 Sterling Silver.
On its reverse is a portrait of Prince Charles and its obverse features the Fourth Portrait of Queen Elizabeth II both designed by Ian Rank Broadley.
These legal tender coins have been struck to proof quality using specially prepared dies and highly polished blanks.
Piedforts are coins which have been especially struck on thicker than normal blanks.
As their name suggests they are closely associated with France, where from the twelfth century, they were apparently issued by the Kings as presentation pieces.
In Britain the practise of striking piedforts is later and less frequent, but medieval and Tudor examples are known.