He was the son of Major Frederick Murray Hay Forbes of the Bengal Staff Corps, and his wife, Honoria Matilda Marshall, daughter of Rev William Knox Marshall and niece of Sir Henry Montgomery Lawrence.
He attended Bedford Grammar School then Elizabeth College, Guernsey.
Training as a doctor he studied at the Middlesex Hospital and spent some years in the Royal Army Medical Corps before becoming a general practitioner (GP) in Church Stretton.
His proposers were Sir William Turner, Douglas Argyll Robertson, Robert C Maclagan and Thomas Annandale.
[1] He was official Examiner to the St John’s Ambulance Association, and was appointed a Knight of Justice of the Order of Saint John of Jerusalem in England on 13 August 1902.