An arrangement (1941–45) according to which the USA supplied equipment to Britain and its Allies in World War II. It was formalized by an Act passed by the US Congress allowing President F. D. Roosevelt to lend or lease equipment and supplies to any state whose defence was considered vital to the security of the USA. About 60% of the shipments went to Britain as a loan in return for British‐owned military bases. About 20% went to the Soviet Union.