A remarkably clear image of what I take to possibly be of a member of Queen's University (Belfast) Officers' Training Corps.
His somewhat unusual shield-shaped cap badge is attached to a corduroy side cap and a double-banked Mills canvas webbing bandoleer crosses his chest. A white whistle lanyard is around his neck and disappears into his pocket. A badge is visible on his shoulder strap but unfortunately it and his cap badge cannot be read so this identification is tentative.
W. Abernethy - Photographer
29 High Street, Belfast, Ireland