Roy's family came from Somerset and their surname was originally Badman, which they changed to Badmin. Roy was born in South London in 1906. He first studied at the Camberwell School of Art (1922-24) and then at the R.C.A. (1924-1928). Roy went on to teach at Richmond Art School (1934), St John’s Wood Art School and at the Central School of Art in London from 1954.

His art was always associated with rural life, and his love of the countryside continuously comes through — with his trees in particular. He worked most of the time in watercolour or pen and ink.
The first colour reproductions of his work were published in The Graphic (1927) and The Tatler (1928).