© 2016 CIPFA.Different types of ‘controllers’ can be distinguished in the public sector. The authors’ research indicates that public sector controllers acknowledge the distinctive characteristics of ‘hybrid’ controllers, but question some of the possible advantages of ‘pure’ controllers. This result could signal a decreasing share of pure controllers and thus a loss of financial expertise in the public sector. This article calls for the controller to be ‘re-invented’ as a professional who combines solid financial expertise with an independent and critical attitude towards overly ambitious politicians and managers. The general public’s support for public sector organizations could be enhanced if strong controllers counterbalance the sometimes too optimistic views of managers and politicians.