The NHS in England underspent its budget by £1.7bn (€2.1bn; $2.6bn) in 2011-12, and most of the money saved can’t be carried over to 2012-13 but must be returned to the Treasury. Only £0.3bn (18%) of the underspend was surrendered through “budget exchange,” the mechanism that allows money to be carried through to the next financial year.

The NHS underspend was the largest in cash terms across Whitehall departments, which collectively spent £5.3bn less than had been budgeted a year ago. A further £1.4bn was saved because the Treasury did not have to distribute funding held in reserve. As a result, while the budgets set a year ago envisaged a fall in public spending of 3.5% in real terms, the outcome was a fall of 5.2%.

The figures, published in Public Spending Statistics on 6 July,1 suggest that departments decided to anticipate the …