The industrialisation of south Wales has always been puzzling. Historians have usually reached for a colonial analogy of some kind to explain it. The Hammonds started the trend by comparing the lack of an industrial tradition and social conditions in south Wales with an African goldfield. Closer observers of Welsh affairs have often agreed, and Perkin made a shrewd summary of their findings in 1969, concluding that the industrial process in south Wales had been semi-colonial.

This train of thought led a careful scholar (in a playful mood) to wonder whether Wales had truly been industrialised; its late nineteenth-century economy was concentrated (and to an increasing extent) on the primary production of commodities, notably coal. Urbanisation lagged behind the average British level, manufacturing was of little importance and most work was of a handwork, almost craft variety. Central features of nineteenth-century industrialisation were missing, and perhaps the beast itself was.

Michael Hechter's book Internal Colonialism: The Celtic Fringe in British National Development 1536–1966 (1975) took this approach to its logical conclusion and extended it to the whole of Wales. For Hechter England had always been the core of British political and economic power and it had constantly dominated the Celtic periphery.