INTRODUCTION: Evidence suggests that health outcomes for hospitalised children in the UK are worse than other countries in Europe, with an estimated 1500 preventable deaths in hospital each year. It is presumed that some of these deaths are due to unanticipated deterioration, which could have been prevented by earlier intervention, for example, sepsis. The Situation Awareness For Everyone (SAFE) intervention aims to redirect the 'clinical gaze' to encompass a range of prospective indicators of risk or deterioration, including clinical indicators and staff concerns, so that professionals can review relevant information for any given situation. Implementing the routine use of huddles is central to increasing situation awareness in SAFE. METHODS AND ANALYSIS: In this article, we describe the realistic evaluation framework within which we are evaluating the SAFE programme. Multiple methods and data sources are used to help provide a comprehensive understanding of what mechanisms for change are triggered by an intervention and how they have an impact on the existing social processes sustaining the behaviour or circumstances that are being targeted for change. ETHICS AND DISSEMINATION: Ethics approval was obtained from London-Dulwich Research Ethics Committee (14/LO/0875). It is anticipated that the findings will enable us to understand what the important elements of SAFE and the huddle are, the processes by which they might be effective and-given the short timeframes of the project-initial effects of the intervention on outcomes. The present research will add to the extant literature by providing the first evidence of implementation of SAFE and huddles in paediatric wards in the UK.