The granting of a £7,000m bilateral loan by the British government to the Republic of Ireland in October 2010 highlights the banking co-dependence of modern Anglo-Irish relations. This article provides a Bank-of-England-centred perspective on the development of Irish monetary institutions from the granting of Irish monetary independence in December 1921 to the establishment of the Central Bank of Ireland in 1943. Irrespective of unresolved Anglo-Irish political issues, the Bank of England's Irish policy during this period was based on a strict adherence to Montagu Norman's key central banking principles of co-operation, exclusiveness and political autonomy. This article identifies that the application of these principles survived both the coming to power of Fianna Fáil (Soldiers of Destiny) in Southern Ireland in 1932 and the outbreak of war in 1939. This article also argues that Norman's adherence to a wider internationalist view of monetary relations played an important role in forcing the overwhelmingly Protestant and pro-union Irish commercial banks, headed by the Bank of Ireland, to come to terms with the reality of Irish monetary independence. In this context, Norman's approach to Southern Ireland parallels the transition from Empire to Commonwealth, which began to emerge in the interwar period.