Co-determinants that have shaped developments in high-tech centres elsewhere are absent in Cambridge, UK, which thus provides a unique case demonstrating how technology enterprise around a science centre can transform local economic activity. But to capture dimensions of cumulative change requires a longitudinal approach. Here indicators that include rates of formation of new firms and their survival and growth over time are used to chart the transformation of collective capabilities. Emerging and growing areas of local competence are identified from data on the sectoral distribution of activity over time and on clusters of related activity in the Cambridge area that point to the emergence of specialized labour markets. The emergence of clusters of firms is related to serial spin-out from the university and local businesses. Channels of diffusion of knowledge and influence among local firms are mapped by graphics of spin-out clusters. Processes mobilizing social capital can be detected in the way technology-based firms evolved a collective response to local problems that could not be solved by individual enterprise.