Following the accession of William IV a new Great Seal was prepared by Benjamin Wyon, the son of Thomas Wyon and his successor as Chief Engraver of His Majesty's Seals. Benjamin Wyon had a precocious talent for the art of engraving. Known first and foremost for his work on medals, he received commissions from a wide variety of institutions and organisations including the Corporation of the City of London, the Royal Botanical Society and the Royal Academy of Music.

On the obverse of the Great Seal of William IV appears an equestrian portrait of the King, clothed in the robes of the Order of the Garter and seated upon a saddle-cloth made of a lion's skin. The background features two warships which, along with the trident in the exergue, allude to the power of the Royal Navy and also to the King's own former service as Lord High Admiral of the Fleet.

On the reverse, Neptune is shown holding his trident to the right of the enthroned King. Britannia stands to the left of the throne while the figures to the far right are Justice and Religion. In the exergue is placed a staff overlaid by the flowers and leaves of the rose, shamrock and thistle.