[2] He won the Byrne Travelling Scholarship awarded by the Scottish Education Department which enabled him to comfortably tour the European continent.
Following the outbreak of World War I, Souter served in the Gordon Highlanders and the Royal Army Medical Corps.
[1] During the post-war period, he garnered a reputation as a talented portraitist, and his many subjects included such personalities as Gladys Cooper, Ivor Novello, and Fay Compton.
[3] Following negative attacks in the national and world press, Souter's wife convinced him to destroy the painting—his greatest work—which he reluctantly assented to do,[4] but he clandestinely retained his preparatory drawings.
[5] Amid the chaos and nightly bombing of World War II, he labored in the Censorship Department as a translator but spent the majority of his time restoring paintings at Windsor Castle.