In 1916, with the Rifle Brigade now serving on the Western Front as part of the New Zealand Division, Barrowclough was regarded as an outstanding officer and in March was promoted to captain. Three months later he was appointed commander of a company in the battalion. In September 1916, he won a Military Cross for his actions during the Battle of the Somme when he led a party in an attack on a German strong point and linked up with the neighbouring British 47th Division. He was also awarded the Croix de Guerre for the same action.