Abstract
This paper examines the historical roots of the current debate about why infrastructure often costs significantly more in Britain than expected. It proposes that while objective factors explain some of the discrepancy, the decisive issue has been repeated swings between ex post pricing and ex ante discounting as temporal frameworks within which managers, politicians and the media design, manage and report major transport infrastructure projects. The evolution of management concepts is highly time and location specific, and so this paper uses London in the 20th century as a case study, identifying a major change in the 1920s and again in the 1970s which decisively rebalanced temporal considerations in financing public transport infrastructure. We conclude that ex ante discounting frames infrastructure projects in ways that encourage rent seeking activity and create principal-agent problems.