But the nod goes to the Chancellor, for two reasons. First, in the long run, the period dismissed by Ed Balls's hero John Maynard Keynes as irrelevant because by then we are all dead, demands that manipulation and deficit spending have not produced the predicted results.

• Franklin Delano Roosevelt's spending splurge during the Great Depression gave voters hope that Herbert Hoover's approach could not, and might therefore have saved capitalism from replacement by other "isms" then on offer. But in the end it took a war to bring full employment;

• President Barack Obama's stimulus package has not made a serious dent in unemployment, and even he is giving thought to reining in spending, or says he is;

• And the previous government's reckless spending and eye-watering deficits have not left in their train a fully employed, prosperous nation.

Second, even if Keynes had it right in his day, that was then and this is now, as the ever-practical economist, only one foot in academe, the other in the real world, would undoubtedly recognise. We live in an era in which the bond vigilantes have ridden against Greece and Ireland, and are saddled up for an assault on Iberia. They are watching Britain for signs that it is unable to bring its deficit under control, and, if such signs appear, will drive up its borrowing costs. Such an increase in interest rates would sharply raise the government's borrowing costs, make business investment more costly and devastate already hard-pressed consumers by sending the cost of their mortgages skyward. In short, Ed Balls is asking Britain to take a greater risk than is George Osborne, especially since Labour's reputation makes its vague promises to cut spending some day less than bankable. If Balls is wrong, and a more leisurely approach to deficit reduction upsets markets, it will be a long while indeed before Britain regains its standing in international bond markets, and it will remain lumbered with an unaffordable public sector and government spending that consumes 50 per cent of its GDP. If Osborne is wrong, and the economy weakens unduly, he has ample room to cut taxes and ramp up spending, assuming he suddenly discovers the Plan B that he now denies exists. So prudence dictates giving the nod to the Chancellor.