He and his wife Nora Holmes (b. 1902, d. 14 May 1993) were for two decades among the most active members of the London Esperanto Club; he served as its president from 1933 until 1952. In this post, as in his editorship of Komuna kantlibro, a book of popular songs, his wife Nora assisted and collaborated with him to such a degree that he often spoke in terms of "our presidency." Harry Holmes's last work, Londono Vokas ("London Calling"), published in 1981, related the 75-year history of the London Esperanto Club.