William IV. 1830-1837. AE Penny (34mm, 18.98 g). Dated 1837. 

GULIELMUS IIII DEI GRATIA, bare head right.
BRITANNIAR REX FID DEF, Helmeted Britannia sitting right on outcropping, holding oval shield and trident; shamrock, rose, and thistle below. 

Peck 1460; Seaby 3845. 

With permission of cngcoins.com, auction CNG 66, Lot: 188. June 2003
SE3845