Between 1979 and 1997, five successive Conservative Secretaries of State headed the Welsh Office, the government department responsible for administratively devolved activity. The extent to which these ministers developed their own 'exceptional' policies at variance with those of central government was much debated, most commonly in relation to economic development. This paper examines such activity to make three arguments. First, exceptionalism took place, but was constrained by the nature of administrative devolution.Second, it often reflected the individual political philosophies of Secretaries of State and their ambitions on the UK's political stage, as opposed to any desire for autonomy. Third, it was a crucial if inadvertent factor behind convincing the electorate that political devolution was both feasible and desirable. Overall, exceptionalism was driven by the Secretary of State's ability to marshal the public sector behind his policy objectives, the momentum of existing institutions and the characteristics of each minister.