This chapter concerns the effectiveness in practice of the current pre-occupation with risk assessment in criminal justice and social services. It examines aspects of the new orientation towards risk and the effects this has had in the probation service and in social work, both of which have moved away from traditional casework methods towards various methodologies of risk assessment. The dynamics of this shift are now well-known (Kemshall, 2003; Oldfield, 2002; Robinson 2003b, 2005). Such change may form part of wider social and political changes, which have been much discussed in the social sciences (Garland, 2001; Lea, 2002; Young, 1999, 2003). The rise to predominance in the United Kingdom of the ‘risk agenda’; the concern by government to protect the public against the risks posed by offenders and other high risk groups is, it can be argued, inextricably connected to ‘the decline of the welfare state’ (Hudson, 2003). In its widest sense, the welfare state is incompatible with the ‘risk society’, in that a commitment to welfare presupposes a desire by tax payers to invest in the reintegration of offenders for the good of society as a whole. The risk society is concerned with excluding those it deems a threat and ensuring that the worthy majority feel protected against such persons. The main aim in this chapter, however, is to identify, on the basis of a small study1 of the implementation of The Offender Assessment System (E-OASys) risk-assessment tool currently in use in the English and Welsh Probation Service, some of the contradictions and problems inherent in the operation of such risk containment techniques by probation practitioners.