In 2017, to celebrate the Queen and Prince Philip's Platinum Wedding Anniversary, the Royal Mint released a Limited Platinum Wedding Piedfort £5 Five Pound Silver Proof Coin struck in solid .925 Sterling Silver.

The reverse has been designed by John Bergdahl depicts an equestrian portrait captures the couple sharing their love of horses side-by-side while the obverse features Etienne Millner's side portrait of Her Majesty Queen Elizabeth II and Prince Philip.
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.