Being on the Reserve, James was mobilised on August 4th 1914, he re-enlisted at Hockerill, Herts and embarked for France on the S.S. Oronsa, on 15th August 1914.
In October, the 1st Bedfordshire Regiment was near Hooge. They suffered several casualties during the month, however, none were reported in the Regiment's war diary on the 19th. The Bedfordshire Regiment War Diary: 15th - 18th November 1914 reported constant intermittent shelling with only mild attacks at various parts of the line with 3 killed and 7 wounded. James was killed on November 19th 1914. A letter from one of his comrades, Company Master Master Sergeant O. H. Perkins said: "Private Prior was killed at Ypres by a German ricochet bullet in the trenches on Nov. 19th last, death being instantaneous. Poor Chap, he was an excellent soldier, one of the best. He was one of the gallant men, who was in the bayonet charge at Ypres & could account for many of the enemy." He was the first Thorley Soldier to fall.