By the 1880s, emigration to North America was rapidly exceeding the entire rural exodus in England and Wales and 'the reserves of potential migration in the rural areas were much reduced'. By then most British emigrants were urban people. In the British case there is a crucial question about the extent of internal mobility in the home context, studied most influentially by Clark and Souden. The campsites, despite their diversity, align in the conditions favourable to migration and emigration, and therefore encourage broader explanations of the British discontinuity. In terms of the structural underpinnings of population mobility and its eventual expression in actual emigration, there are long lines of causation as well as matters of contingency in the story. In the end the rural sector expanded positively and unprecedentedly, to the demands generated by the essential needs of the expanded and industrialising population of the country.