The World War of 1914–18 undoubtedly had a profound impact upon Great Britain and Ireland and it is tempting to see it as a watershed of revolution. On balance, however, despite the undoubted changes which occurred, the period between 1918 and 1939 appears more as an interlude in which old and new elements were still intermingled and the future of Britain and Ireland was still unclear. It was still presumed, for example, that Britain was a great world power, an attitude which seemed persuasive because of the fact that the United States and the Soviet Union largely retreated from their full roles in world affairs. The real weakness of the British empire was not to be exposed until 1940 when it became clear that Britain was dependent upon American aid for the continuance of the war.

Of the internal changes which occurred within the British Isles during this period one of the most important was the emancipation of women, although the impact of this varied throughout ‘the British Isles’. It was most marked in southern England, less so in northern England and least of all in Ireland, particularly in the newly established Irish Free State.

In the context of the history of the United Kingdom, the impact of the First World War in 1914 had been to arouse a sense of ‘Britishness’ among many sections of the population.