[5] Foxon's civil service career began with a short period in the Ministry of Town and Country Planning,[5] but in 1950[6] he was appointed an assistant keeper of printed books at the British Museum Library.
[9] In an obituary in Studies in Bibliography, James McLaverty described Foxon as "perhaps the most distinguished British bibliographer of the second half of the twentieth century.
"[10] His English Verse, 1701–1750: A Catalogue of Separately Printed Poems with Notes on Contemporary Collected Editions (1975) was ground-breaking.
[14][15] He wrote The Technique of Bibliography (1955) and, with James McLaverty, he authored Pope and the Early Eighteenth-Century Book Trade (1991).
[17] Foxon had met his wife June while they were both serving at Bletchley Park; she was the daughter of the cinema proprietor Sir Arthur Jarrett.