The United Kingdom of Great Britain and Ireland—then consisting of England, Scotland, Wales, and the whole of Ireland—was one of the Allied Powers during the First World War of 1914–1918, fighting against the Central Powers (the German Empire, the Austro-Hungarian Empire, the Ottoman Empire and the Kingdom of Bulgaria). The state's armed forces were reorganised—the war marked the creation of the Royal Air Force, for example—and increased in size because of the introduction, in January 1916, of forced conscription for the first time in the kingdom's history as well as the raising of the largest all-volunteer army in history, known as Kitchener's Army, of more than two million men.[1] The outbreak of war has generally been regarded as a socially unifying event,[2] although this view has been challenged by more recent scholarship. In any case, responses in the United Kingdom in 1914 were similar to those amongst populations across Europe.[3]