The thesis seeks to examine practices of British economic warfare towards Germany during the First World War. In particular it focuses on the development of methods to weaken the German will for war by convincing Germany that winning, a military victory would be pointless if it destroyed her commercial position. In doing so it brings together two separate elements of British economic warfare -trade war and control of raw materials - into a single strategy with a unified aim. It explores British attempts to destroy Germany's foreign trade organisation in order to induce German commercial interests to end to the war through fear of losing post-war markets. However, in attempting this Britain was hampered by wartime conditions which interrupted the provision of shipping, capital and goods needed to make the policy a permanent success. Many Germans believed their production and marketing methods would enable them to reclaim their share of world trade after the war. This was providing there was no punitive post-war penalisation of German trade. In June 1916 the Allies met in Pans to outline such a plan which involved the creation of an economic bloc to isolate Germany from the world trading system. At this point supplies rather than markets became the focus of economic warfare against Germany. With control of the world's raw materials, the Allies hoped to create an economic weapon capable of threatening German post-war recovery and thus have an important psychological impact on the German commercial mind-set. However such a scheme had to contend with the differing variables of Allied, American and Imperial interests. It is hoped the thesis will not only illuminate British economic policies during the First World War, but also contribute to the debate amongst historians on the relationship between international economic relations and foreign and security policies in the twentieth century.