Instead of becoming a barrister, Thomson accepted the position of deputy governor at HM Prison Liverpool, after his name was suggested for the post due to a personal acquaintance with Sir Evelyn Ruggles-Brise, a fellow Old Etonian who had stayed with Thomson in Tonga.
Like his predecessors, Patrick and John Cobbold, Peter Hill-Wood (Chairman of Arsenal), and HRH Prince William (President of the Football Association), Sheepshanks is an Old Etonian.
In 1909 four Old Etonian philanthropists founded Eton Manor Boys' Club to provide sporting facilities in the Hackney area, purchasing the former Manor Farm in 1913.