The UK National Health Service (NHS) workforce has recently seen the arrival of the Graduate Mental Health Worker (GMHW) in primary care. We established a Quality Improvement Collaborative to assist in embedding this new workforce in one Strategic Health Authority Area of England. The intervention utilised 'collaborative' technology which involves bringing together groups of practitioners from different organizations to work in a structured way to improve the quality of their service. The process was evaluated by an action research project in which all stakeholders participated. Data collection was primarily qualitative. During the project, there was an increase in throughput of new patients seen by the GMHWs and increased workforce satisfaction with a sense that the collaborative aided the change process within the organizations. Involvement of managers and commissioners from the Primary Care Trusts where the GMHWs were employed appeared to be important in achieving change. This was not, however, sufficient to combat significant attrition of the first cohort of workers. The project identified several barriers to the successful implementation of a new workforce for mental health problems in primary care, including widespread variation in the level and quality of supervision and in payment and terms of service of workers. A collaborative approach can be used to support the development of new roles in health care; however, full engagement from management is particularly necessary for success in implementation. The problems faced by GMHWs reflect those faced by other new workers in healthcare settings, yet in some ways are even more disturbing given the lack of governance arrangements put in place to oversee these developments and the apparent use of relatively unsupported and inexperienced novices as agents of change in the NHS.