The aim of the paper is to establish the extent to which design teams are co-operative in practice. The objective is to explore the extent to which co-operation, measured through the competence trust, is present within the design team, and between the client and design team. Trust is explored through a framework of trust, a survey proving data based on the framework. The data are sourced from the design team, real estate consultants and from one of the leading UK property developers undertaking a large multi-use redevelopment in a prominent location in the heart of London. The main findings are that there is a high level of overall trust, the levels increasing as other parties—namely the agents and client—are involved, which has wider lessons for collaborative working between all those responsible for delivering projects. The quantity surveyor/cost consultant has a professional role that inherently creates tensions in the relationships, giving rise to a need for them to develop a broader set of competencies beyond immediate professional requirements. There is also an indication that the organizations involved appear to rely on individuals taking responsibilities for the presence of trust, rather than taking opportunities to develop strategies and actions to facilitate trust.