The rhetoric of partnership is ubiquitous in the current policy context. In education, partnerships take a number of forms among which is "interorganisational collaboration" (IOC), defined as a partnership between institutions/organisations aimed at developing synergistic solutions to complex problems. But policy has a tendency to veneer, obscuring its enactment. The purpose of this paper is therefore to examine what such partnerships look like on the ground. Here we present an empirical analysis which aims to produce knowledge about the working of such collaborative groups and to provide insights into leadership within such partnerships. Drawing on communicative constitution of organisations operationalised within a schema for understanding the emergence of collective identity in IOC, we undertake an analysis of meetings held by a working group comprising academics and local authority staff set up to develop masters-level work-based professional learning for teachers. We ask, how do professionals working within different contexts create a collective identity that supports decision-making, and what are the implications for leadership?