The formal ties that bind collaborating organisations are often assumed to be reinforced by the relationships of individual employees, and these by trust. So, too, are the personal networks by which employees acquire much of the information required for the organisation's innovation. It is easy to assume that personal networks should support collaborative arrangements. It is also tempting for managers to ensure that they do by bringing them under organisational control. This paper investigates collaboration in Esprit, the European Commission's programme for research in information technology. It finds personal networks, and considers the implications for innovation of attempts to render these networks compatible with collaboration.