Was British confidence that the Commonwealth could bolster its international status and extend its global reach after the Second World War a product of self-delusion or nostalgia? This paper examines three crucial aspects of relations between Britain and Canada, Australia, New Zealand and South Africa in the 1940s -diplomacy, economics and defence -to show the extensive and tangible support that the 'old dominions' extended to Britain. They opted to back Britain because it served their individual national interests well. British hopes that the post-war Commonwealth would be an effective association were founded on ample evidence, although the British desire to lead and dominate was confounded by the fact that Ottawa, Canberra, Wellington and Pretoria were national centres in their own right.Although by 1945 British officials, political leaders and citizens eagerly anticipated the end of the Second World War, the return to peace presented serious problems for British influence and standing in the post-war world. Britain had been devastated by the war. Its two ranking allies, the United States and Soviet Union, had surpassed Britain as world powers. More durable causes of decline were also increasingly evident. But neither the wartime coalition government nor the Labour government elected in July 1945 was resigned to Britain's decline. They understood that the challenges to British power had both proximate and long-term causes and therefore required different solutions, including borrowing money to finance post-war reconstruction, co-operating with Washington, rebuilding the export trade and acquiring an independent nuclear weapons capability. The goal of these various tactics was the same: to ensure that Britain remained a global power in the post-war world. Few seriously questioned this priority, which was based on a conviction of Britain's historic and rightful place in the international community and fuelled by a persistent 'Great Power psychology'. 1