Rooted in a geopolitical vision of enduring maritime Empire, the proposal that Britain and its dependencies should form a single autarkic economy, raising tariffs against the rest of the world but extending preferential rates to one another, attracted considerable support once it was clear, in the 1890s, that the British economy was failing to keep pace with Germany. The persistent British attachment to free trade survived the First World War but was finally overcome 1931 as steeply declining relative competitiveness of British manufacturing industry coupled with more autarkic trade policies in the United States and elsewhere coincided with an unprecedentedly sharp cyclical downturn in world demand and trade after 1929. The system of imperial preference was partially applied to the self-governing dominions following the Ottawa Conference of 1932 and was underpinned by formalization of a largely coextensive sterling area, especially after the imposition of exchange controls in 1939. The system gradually withered after 1945 as changing trade patterns diminished the importance of intra-Commonwealth commerce while margins of preference were eroded by inflation and British membership of the European Free Trade Association (EFTA). The end, effectively, came with the twin blows of sterling devaluation 1967 followed by British entry to the European Economic Community (now the European Union) in 1973.
— Charles Jones




