[6] Arnup was born in London and began studying at the Kingston School of Art at the age of thirteen.
[8][9] In 1955 she won the Royal Society of British Sculptors' Feodora Gleichen Award for women artists.
[8] Among Arnup's most notable commissions was a work for the Duke of Edinburgh’s 80th Birthday, depicting his Fell Pony Storm.
[5] In 1971 she cast a silver leopard which was presented to HM Queen Elizabeth II by the City of York.
[12] In 2015 at the age of 85, Arnup suffered a stroke while modelling a horse for a large scale sculpture at stables near Thirsk.