The regiment also raised many service battalions during the war, specifically for war service only. The 5th (Service) Battalion was part of the First New Army, part of Kitchener's Army, and joined the 35th Brigade attached to the 12th (Eastern) Division. They saw their first action in 1915 at Loos. Then, in 1916, the battalion fought at the Battle of Albert and Pozières in 1917. In 1918 the 5th Battalion was transferred to the 36th Brigade, still with 12th Division.