Abstract
Developments in industrial organization contributed to the lack of diversification in Britain's older industrial areas during the interwar period. The large-scale firm had not yet developed in appropriate industries to the point where large numbers of branch plants could be sent to the depressed areas (as they were after World War II), even if interwar macroeconomic policy had been more expansionary. At the industry level, barriers to new entrants and restrictive practices were high in the 1930s, precisely the period when the need for structural change in the depressed areas was most apparent.