The use of nurses' holding power is a poorly explored aspect of psychiatric inpatient care. This study examined the use of Section 5(4) at the Maudsley Hospital, London, since the introduction of the 1983 Mental Health Act. Between 1983 and 1996 nurses' holding powers were used on 25 occasions. Seventy two per cent of patients detained under Section 5(4) of the Mental Health Act 1983 were subsequently detained under Section 5(2). Results were broadly consistent with previous studies, although some significant inconsistencies were observed which can probably be attributed to small sample sizes. Further, multicentre research is needed in order that substantive conclusions can be drawn.