As the chancellor prepares his Budget and US President Donald Trump shapes his economic plan, commentators are urging both to engage in significant new spending on transport infrastructure.
The conventional case was articulated well by Times columnist Oliver Kamm last week. Only the government can undertake the investment and planning necessary for complex projects such as new rail lines, we were told, and with borrowing costs low, a state splurge would boost demand in the short term and enhance long-term growth prospects too — a so-called “win-win” policy. Sounds a no brainer, huh?

Not quite. For starters, you would undertake very different projects depending on whether you wanted a short-term boost to demand or to improve the economy’s long-term health. As President Obama once acknowledged, most things worth doing are not “shovel ready”, not least because of state land use planning and environmental laws.