In 2005, to commemorate the 200th anniversary of Nelson‘s death and the Battle of Trafalgar, the Royal Mint has issued two special commemorative Piedfort £5 Five Pound Silver Proof Coins.
James Butler RA has designed the Nelson £5 Five Pound Crown which features a portrait of Nelson in the uniform of Vice Admiral. 
The Trafalgar £5 Five Pound Crown is the creation of Clive Duncan and features the Victory, Nelson's flagship at the Battle of Trafalgar, in full sail.
Both £5 Five Pound Crowns show Ian Rank Broadley's portrait of Queen Elizabeth II on the obverse.
Piedfort's 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 practice of striking Piedfort's is later and less frequent, but medieval and Tudor examples are known.
These legal tender coins have been struck to proof quality using specially prepared dies and highly polished blanks.