A crucial feature of the US development contracts was that they stimulated both machine tool development and control systems. Though numerical control systems were born in the electronics and computer industries, to work effectively they required important applied development work on machine tools. The size, homogeneity and early development of the American market do much to explain why American companies lead the world industry in numerical control. Cincinnati went into machine tools, originally, as a user. In Britain the machine tool companies showed little interest until around 1960. European manufacturers have therefore faced American manufacturers who have had a head start, in terms both of scale and of continuous experience of a more sophisticated market. In the UK and the rest of Europe, by contrast, growth of the market was slower. Ferranti demonstrated in the NC field that European brains are capable of path-finding in a major field of innovation. The pressures of scale thus help to explain the merger.