Elliot was involved in the Empire Marketing Board from October 1927, having been appointed president of the Imperial Research Conference in Westminster Hall. and with John Boyd Orr began a project that conducted experiments in 1927 proving the value of feeding free milk to children in schools, and this persuaded Elliot to extend the pilot scheme to all Scotland's schools by legislation. Elliot was a supporter of the Empire Marketing Board Film Unit and its work on documentary films, particularly those of John Grierson, including "Drifters" in 1929.