<P> During World War I , there were three distinct British Armies . The `` first '' army was the small volunteer force of 400,000 soldiers , over half of which were posted overseas to garrison the British Empire . This total included the Regular Army and reservists in the Territorial Force ( TF ) . Together , they formed the British Expeditionary Force ( BEF ) , which was formed for service in France and became known as the Old Contemptibles . The ' second ' army was Kitchener 's Army , formed from the volunteers in 1914 -- 1915 destined to go into action at the Battle of the Somme . The ' third ' was formed after the introduction of conscription in January 1916 , and by the end of 1918 , the British Army had reached its maximum strength of 3,820,000 men and could field over 70 divisions . The vast majority of the British Army fought in the main theatre of war on the Western Front in France and Belgium against the German Empire . Some units were engaged in Italy and Salonika against Austria - Hungary and the Bulgarian Army , while other units fought in the Middle East , Africa and Mesopotamia -- mainly against the Ottoman Empire -- and one battalion fought alongside the Japanese Army in China during the Siege of Tsingtao . </P>
where did the british army fight in ww1
France Belgium Italy Salonika Middle East Africa Mesopotamia China