An essential dimension of urban policies and problems in our period is the experience of the ‘Third World’, which provided a field of activity for the professions that we have been discussing. Besides this — and however alien or exotic it may sometimes have seemed — it was a vital part of the continuum in which our own urban culture existed. From Britain’s imperial past, and the natural egocentricity of its planning system, it was often assumed that British urban culture was indepen­ dent and in many ways superior, but it was in fact embedded in a global economy and framework of ideas. Nor was the traffic in ideas all one way; and the new ideas that Third World experience generated were of crucial importance for British planning and throw much light on the relationships between people and environments, and on the deep contradictions of urban development that will concern us in the later chapters of this book.