This paper explores the implications of the Certificate of School Business Management programme and its impact to date, and argues that it may prove to be a significant development in changing the culture of school leadership. It presents a view of leadership that fits a "loose-tight" model of organisational management, with less operational control by headteachers: this perspective is labelled "leadership at all levels". The key contention here is that School Business Managers should be part of the leadership of the school, and regarded as "leaders backing leaders". However, despite strong evidence of the effectiveness of the approach, the authors note that it has not yet been widely accepted in English schools, and offer an explanation for this, citing three obstacles to change. The paper argues that external catalysts, and specifically the Bursar Development Programme, have begun to change this situation. The evidence for this assertion is based on impact evaluation data produced by National College for School Leadership, an analysis of self-evaluation feedback provided by candidates on the programme and qualitative data from three case studies. The conclusions reached are that the programme is instrumental in producing innovations in organisational structure and is leading to attitudinal change with regard to the value of different expertise in schools: both of which reflect implementation of the model of leadership at all levels. It is noted, however, that this is still at an early stage of development. (Contains 2 tables and 1 figure.)