The anti-social behaviour order has proved to be one of the more controversial elements of the Government's agenda for law and order. On the face of it, however, little of that controversy is reflected in the court process, where the 'success rate' of applications for such orders is extremely high. Drawing on recent research on the use of ASBOs against children, this article aims to explore some of the factors that determine whether an application against a young person below the age of 18 years is granted. It is argued that while courts generally require strong evidence to establish the young person's involvement in anti-social behaviour, less attention is paid to the issue of whether an ASBO is necessary to prevent further incidence of misconduct. It is further contended that necessity is overlooked, in part, because magistrates and district judges (and defence solicitors) tend to assume, sometimes erroneously, that applications for ASBOs against children are only initiated where other measures have been tried and failed.