This article reports on the emotional impact of Threshold Assessment on teachers and schools. Using data from an ESRC funded project, 'The impact of Performance Threshold Assessment on teachers' work' (ESRC R000239286), we seek to contribute to a growing literature on teachers' emotions by sharing some of the insights gained from 76 interviews undertaken in nine case study primary and secondary schools between 2001-2003. The research has revealed a number of (apparently) unintended consequences of Threshold Assessment as well as considerable variability of experience. We underline the significance of contextual factors in the way that the policy was handled in schools and in the degrees of vulnerability and exposure experienced by teachers as they struggled to come to terms with the demands of 'performativity'.