Patients can experience unexpected deterioration in their physiological condition that can lead to critical illness, cardiac arrest, admission to the intensive care unit and death. While ward staff can identify deterioration through monitoring physiological signs, these signs can be missed, interpreted incorrectly or mismanaged. Rapid response systems using early warning scores can fail if staff do not follow protocols or do not notice or manage deterioration adequately. Nurses often notice deterioration intuitively because of their knowledge of individual patients. Patients and their relatives have the greatest knowledge of patients, and can often pick up subtle signs physiological deterioration before this is identified by staff or monitoring systems. However, this ability has been largely overlooked. Call 4 Concern (C4C) is a scheme where patients and relatives can call critical care teams directly if they are concerned about a patient's condition- it is believed to be the first of its kind in the UK. A C4C feasibility project ran for six months, covering patients being transferred from the intensive care unit to general wards. C4C has the potential to prevent clinical deterioration and is valued by patients and relatives. Concerns of ward staff could be managed through project management. As it is relatively new, this field offers further opportunities for research.