Percy enlisted as a private in the 17th Middlesex Battalion (Public Schools Battalion) on April 30 1915. He travelled to France from Folkestone on April 221916. He was in Etaples until May 4 when he joined a French Mortar Battalion. On October 19 1916 he was sent back to England to join the Officer Cadet Unit. He joined the Battalion in Oxford on December 1 1916. He was later gazetted (April 25 1917) as a 2nd Lieutenant in the Durham Light Infantry.
In June 1917 the Durham Light Infantry was holding the line at Loos between Boyau 51 to Cameron Alley. A Coy Right Front, C Coy Left Front, B Coy in the village line and D Coy in Reserve battalion HQ at Tosh Keep. Percy Thompson was recorded as killed in action on June 11 1917, during the tour of duty in the trenches between June 9 and 18 . While his death is listed in the War Battalion Diary, the specific cause was not given. There was a raid during this time on German trenches on the 15th but he was reported killed by this time. There were patrols out before this, so that is a possible reason but if so, it would perhaps have been stated as he was a 2nd lieutenant.
A letter from his father concerning his effects reads: “I am having them sent to my son’s residence, as at the present time, his mother could not bear the sight of these his effects coming home.” These effects included a wrist watch, a bracelet, a ring, a cheque book, a note case, and a half franc note which was a souvenir.
