Watch List notes:

Commemorative Medals and Tickets, Isaac Newton (1642-1726), 250th Anniversary of Death, large patinated struck bronze medal, 1976, by Christopher Ironside, OBE, FSIA, FRBS (1913-1992), for the Royal Mint, bewigged bust three-quarters r., facsimile signature in field to r., rev. Royal arms and supporters of William III, THE ROYAL MINT – SIR ISAAC NEWTON WARDEN 1696-1699 MASTER 1699-1727, 109mm., in Royal Mint red leatherette case of issue, virtually mint state and extremely rare
The medal does not appear in a published listing of his medallic work nor on the Royal Mint website; the British Museum specimen was purchased from the artist's son in 2006.