Penlee House, Penzance holds a set of original pencil drawings for the Penzance and St Michael's Mount aquatints (produced in 1813) by Daniell for Richard Ayton's book A Voyage Around Great Britain.

In 1799 Daniell entered the RA Schools, following in the footsteps of his uncle Thomas DANIELL (1749-1840) who had become responsible for bringing up his orphaned nephew. This was after William had accompanied his uncle to India, where Thomas worked as an engraver after his own training at the RA Schools (1773) and exhibiting at the RA; hence William was already an experienced landscape painter. 

In 1813 William embarked on a trip around the whole coast of Great Britain, and his resultant works are recognised as his greatest artistic triumph, and a high point in the history of aquatint engraving. He started his journey at Lands End, going up the northern coast of Cornwall, but did not complete his circuit of Britain until August and September 1823, when he did the southern coast of the county, taking in Looe, Polperro, Fowey, Mevagissey and Falmouth. By this juncture, he had been elected a Royal Academician (1822) - the final vote being between him and John Constable. (Tovey, 2021 - see below).

His brother Samuel DANIELL (1775-1811) was a topographical artist.