Purpose– The purpose of this paper is to explore the psychological processes involved in spontaneous co-operation by survivors of mass emergencies, and the possible implications this may have for emergency responders.Design/methodology/approach– A qualitative interview study was conducted with 12 survivors and witnesses of the 7 July 2005 London bombings. Data were subjected to thematic analysis.Findings– Spontaneous co-operation amongst survivors often emerged, and this was a function of a common identity that grew out of a sense of shared fate amongst those affected. Some social influence that encouraged co-operation also occurred, and this was dependent upon whether there was a sense of shared identity between source and target of influence.Research limitations/implications– Evidence was only collected from a sub-set of one incident (7/7), thus limiting possible generalisability of the findings. Further research into comparable situations would provide a better understanding of the processes underlying mutual co-operation and support amongst emergency survivors.Practical implications– Uninjured bystanders in emergencies can act as “zero-responders”, and so may become a useful resource which can be utilised by the emergency services in mass emergencies.Originality/value– This is the first paper to explore in detail the social influence processes underlying spontaneous co-operation amongst survivors of emergencies, and will be of use to emergency responders.