A multi-faceted, longitudinal and prospective collaborative inquiry was initiated in December 2002 with one half of the cohort of operating theatre personnel in a large, acute UK hospital serving a mainly rural population. The same intervention was introduced in January 2004 to the other half of the cohort. The project aims to improve patient safety through a structured educational intervention focussed upon changing teamwork practices. This article reports one critical element of the larger project - changing teamwork climate as a necessary precursor to establishing an interprofessional teamwork culture. The aggregate of individual, unidirectional attitude changes across a large cohort constitutes a change in climate. This shift challenges the conventional culture of multiprofessionalism, where uniprofessional identification (the "silo" mentality) is traditionally strong.