Having served with an artillery regiment in German East Africa, Thomas Sinclair Harrison joined the Royal Flying Corps in April 1917. He was posted to 29 Squadron on the Western Front in May 1918. Flying the S.E.5a, Harrison became the highest scoring ace in his squadron. During World War II, Major Harrison was an intelligence officer in the South African Air Force.
Distinguished Flying Cross (DFC)
Lieut. Thomas Sinclair Harrison.
When on wireless interception duty this officer engaged three enemy machines, shooting down one in flames. He was then attacked by three scouts and a two-seater; the latter he shot down. During the last few weeks he has further accounted for three hostile aeroplanes and a balloon, displaying vigour and gallantry in attack.
Lieut. Thomas Sinclair Harrison. D.F.C.
Bold in attack, skilful in manoeuvre, this officer never hesitates to engage the enemy, however superior in numbers. On October 2nd he, with three other machines, took part in an engagement with eight Fokkers; four of these were destroyed, Lieut. Harrison accounting for one. On another occasion he, in company with four others, engaged fa large formation of Fokkers; three of these were destroyed, one by this officer. In all he has destroyed twenty enemy machines.