While he was chief executive of British Airways, Rod Eddington argued for the UK to invest in infrastructure in order to stay competitive. Now he has the opportunity to demonstrate the case in his review for the UK Treasury and the Department for Transport of the long-term links between transport and productivity, growth and stability. We look to him to prove what most business leaders take for granted: that investing in transport enhances gross domestic product and ultimately increases the Treasury’s tax take.

Assuming his review proves the case, what will the government do? Most in­vestment in transport, for which many cities are crying out, requires significant public sector borrowing, but Gordon Brown is bumping up against self-imposed constraints. The chancellor of the exchequer introduced his code for fiscal stability in 1998. It wisely in­cluded the “golden rule” that, over the economic cycle, the government will borrow only to invest and not to fund current spending; and the “sustainable borrowing rule” that public debt as a proportion of national in­come will be held at “a stable and prudent level”. It is the latter that now poses the problem. To meet it, Mr Brown undertook that net debt would be maintained at below 40 per cent of GDP.