Lonsdale Battalion events that took place on 12 August.
- Battalion remains in trenches in the front line (Cambrin Sector). Early in the morning 1 NCO and 4 other ranks (MG) are hit by an explosive bullet; one man is killed.
- Hostile artillery is very quiet during morning.
- At 4:10pm 11th Border artillery bombards the German lines for approximately 15 minutes. 
- At 8:00pm the Germans start a bombardment that lasts for about an hour; 11th Border artillery replies very effectively causing the enemy to cease their fire. 
- Three other ranks wounded in the bombardment.
- The Commanding Officer visits the trenches at 9:30pm.
- Deaths: Richard Hartness (19505 Pte.).