Between 1900 and 1925 the British Government evolved a policy concerning agricultural development in West Africa by which expatriate-owned plantations, especially for oil palms, were excluded. This prohibition created as many problems as it solved, for the Nigerian Government in particular faced the problem of competition in the international palm-oil and kernel market from plantations in South-east Asia and the Belgian Congo. In the 1920s the Nigerian Government went to considerable effort to entice British capitalists to invest in palm-oil processing (but not production), but to no avail. In the 1930s the Government concentrated on trying to rehabilitate the oil-palm industry by encouraging the establishment of small, native-owned plantations, improving native methods of oil extraction and controlling the quality of palm-oil and kernel exports. This policy was beset with difficulties of finance, inadequate research and the effects on land tenure systems. It failed, and the Nigerian palm-oil export industry lost its place in the world market.
British trusteeship does not appear to have been a positive policy as far as economic development was concerned. It created a dilemma which the colonial authorities were not equipped to solve in the economic and political context of the inter-war period.