As the UK general election approaches, voters are being seduced by promises from all the parties about how much they will invest in improving the nation’s infrastructure over the next Parliament. What should we make of these promises? This question is not just about political credibility (or even honesty); it has a hard economic edge. The injection of a slew of new major and minor projects would have implications for the quality of public services, employment, inflation, taxation and government debt. It is worth asking ourselves how much of this spending will actually happen—and when.