A cross-sectional survey was conducted of qualified nurses between 18 April and 18 October, 2010. Qualified nurses attending continuing professional education courses at a large university in central London were invited to participate in the study. Potential respondents were given a study information sheet and a questionnaire by the investigator. Completed questionnaires were collected immediately by the investigator or returned by mail to the research team using Freepost addressed envelopes. Questionnaire completion was anonymous so that it was not possible to follow up non-response. Ethical approval was obtained from the University Ethics Committee.