Background. The slogan "Suicide prevention is everyone's business" has been used in a number of campaigns worldwide in recent years, but most research into suicide prevention has focused on the role of medical professionals in identifying and managing risk. Little consideration has been given to the role that lay people can play in suicide prevention, or to the resources they need in order to do so. The majority of people who take their own lives are not under the care of specialist mental health services, and around half have not had recent contact with their general practitioner. These individuals are not known to be 'at risk' and there is little or no opportunity for clinical intervention. Family members and friends may be the only ones to know that a person is troubled or distressed, and their capacity to recognise, assess and respond to that distress is therefore vitally important. This study aims to discover what the suicidal process looks like from the point of view of relatives and friends and to gain insight into the complex and difficult judgements that people have to make when trying to support a distressed individual. Methods/Design. The study uses qualitative methods to build up a detailed picture of 15-20 completed suicides, aged 18-34. Data are gathered by means of in-depth interviews with relatives, friends and others who knew the deceased well. In each case, as many informants as possible are sought using a purposive snowballing technique. Interviews focus on the family and social network of the deceased, the ways in which relatives and friends interpreted and responded to his/her distress, the potential for intervention that may have existed within the lay network and the knowledge, skills and other resources that would have helped members to support the distressed individual more effectively. Discussion. The study will inform interventions to promote public mental health awareness and will provide a basis on which to develop community-focussed suicide prevention strategies.