In 2018, to celebrate the 70th Birthday of Prince Charles, the Royal Mint released a very Limited Issue Prince Charles Piedfort £5 Five Pound Platinum Proof Coin struck in solid fine 999.5 Platinum weighing three ounces of pure Platinum.
The reverse designed by Robert Elderton depicts a profile portrait of Prince Charles while the obverse features the Fifth Portrait of Queen Elizabeth II designed by Jody Clark.
These legal tender coins have been struck to proof quality using specially prepared dies and highly polished blanks.
Piedforts are coins which have been specially 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.