Mike and David return to the questions arising from Boris Johnston’s “Build-build-build” policy. In a wide ranging discussion they cover international development in Africa, the political decision-making system as it contrasts with economic decision-making and the fact that, with modern technology, small is beautiful. Illustrating thoughts with Empire railway-building and Glasgow trams, they move on to the unseen effects of state infrastructure investment. In the end, the destructive effects of perverse state policies are considered.