A key component of the NHS (and global) response to the COVID-19 pandemic has been to reinforce acute and critical care capacity, through an unprecedented re-deployment of personnel from different care pathways into fluid teams consisting of volunteers, student doctors and nurses, and in some cases military personnel [1-4]. These COVID-teams provide a unique opportunity to examine the interaction of many of the established factors for successful delivery of medical teamwork and care. Current evidence suggests that without common teamwork, shared communication patterns and clear leadership structures, the ad-hoc and fluid nature of these COVID-teams increases risk to patient outcomes, delivery of care [5-9] and team member resilience, mental-health and retention [10,11]. This project will examine how non-technical factors for healthcare delivery (leadership, social support & cohesion, communication, shared mental models, co-ordination) and expected moderating factors (occupational background, preparedness, work-life balance, home situation, proximity, workforce allocation models) impact on perceived COVID-teamworking and performance, individual team member well-being and team member employment retention intentions. It will be a mixed methods cross-sectional exploratory study of COVID-team members, clinical directors and senior hospital managers across a wide range of partnered NHS Trusts. Qualitative interviews will identify key themes and will be followed up by a more widely recruited confirmatory survey examining longer term individual well-being and retention intentions. Throughout, there will be a high emphasis on rapid dissemination of results to NHS partners and wider medical and other stakeholders to inform evidence-based workforce guidance and accelerate team-working theory, practice and policy.