The British Army in World War 2 During the First World War, the British Army was transformed from a voluntary, professional force backed up by a voluntary reserve into a 'national' army recruited by conscription. It was able to make this transition without a material decline in its' effectiveness, and this is a considerable credit to the regimental system and the calibre of its personnel. At the start of the war, there was probably no or very little anti-German feeling amongst the ranks of the army, but instead probably a preparedness to take on anyone. Once war was declared and mobilization ordered,