The groat is a fourpence coin. This denomination was re-introduced for circulation in 1836 at recommendation of Joseph Hume and nick-named after him "Joeys". Circulation issue groats had the Britannia reverse; Maundy Groats did not.
Bare head of King William IV facing right; around, GULIELMUS IIII D:G: BRITANNIAR: REX F:D:.
Figure of Britannia, draped and wearing helmet, seated facing right holding trident and resting right hand on an oval shield which bears the crosses of the Union flag; around, FOUR PENCE; in exergue, the date 1837.