"In the long run you have got to pay for it... You can't just keep borrowing forever."

Breaking with current economic orthodoxy, Robert Barro, Paul M Warburg Professor of Economics at Harvard University, said large spending plans should be undertaken only if they can be justified financially on their own merits. Any other spending plans end up costing the country even more than the initial outlay as interest on the debt has to be paid and the deficit cleared.

“In the long run you have got to pay for it. The medium and long-run effect is definitely negative. You can’t just keep borrowing forever. Eventually taxes are going to be higher, and that has a negative effect,” he said.

“The lesson is you want government spending only if the programmes are really worth it in terms of the usual rate of return calculations. The usual kind of calculation, not some Keynesian thing. The fact that it really is worth it to have highways and education. Classic public finance, that’s not macroeconomics.”