Despite a growing recognition of the significance of farmer-led irrigation, externally engineered and induced schemes remain a popular model for irrigation development in sub-Saharan Africa. These have had a mixed record, and many have been widely critiqued. Nonetheless, schemes that were initiated under colonialism have been rehabilitated and new schemes are still being developed. This paper interrogates the continuing attraction of this model for irrigation, asking how and why it persists. Is the fact that engineering is so central to irrigation schemes another example of ‘high modernism’, as Scott might argue? Analysis of the history and current policy-making context of a new irrigation scheme in Malawi suggests a picture that is more complex, in which practical engineering considerations combine with narratives of modernisation and political imperatives to create momentum and lock-in. Understanding this, and why lessons from the past inadequately shape future-directed planning requires interrogation of the positionality of those involved, including state, donors and private sector actors and the political, economic and discursive fields in which they operate.