Aim and objective To understand how nurses and midwives manage informal complaints at ward level. Background The provision of high quality, compassionate clinical nursing and midwifery is a global priority. Complaints management systems have been established within the National Health Service in the UK to improve patient experience yet little is known about effective responses to informal complaints in clinical practice by nurses and midwives. Design Collaborative action research. Methods Four phases of data collection and analysis relating to primarily one National Health Service trust during 2011–2014 including: scoping of complaints data, interviews with five service users and six key stakeholders and eight reflective discussion groups with six midwives over a period of nine months, two sessions of communications training with separate groups of midwives and one focus group with four nurses in the collaborating trust. Results Three key themes emerged from these data: multiple and domino complaints; ward staff need support; and unclear complaints systems. Conclusions Current research does not capture the complexities of complaints and the nursing and midwifery response to informal complaints. Relevance to clinical practice Robust systems are required to support clinical staff to improve their response to informal complaints and thereby improve the patient experience.