He will warn that “a hurricane is about to hit” Britain’s economy, in the most dramatic warning yet by a Labour politician that the coalition’s deficit reduction programme could prompt a double-dip recession.
Balls will label George Osborne, chancellor, as a “growth denier”, who is ignoring warning signs of a global slowdown.
“What he is now doing is the equivalent of ripping out the foundations of the house just as the hurricane is about to hit,” he will claim.
As he admits, his view is contrary to that of Mr Osborne, the Treasury and Mervyn King, Bank of England governor. But he will cite Clement Attlee, who set up the welfare state after World War 2 instead of immediately paying down post-war debts.
“We have just experienced the biggest global financial crisis in a century, an event as momentous in historical and financial terms as war, famine or plague,” he will say.
Of course, if this turns out to be wrong, it will be damaging to Balls’ economic reputation – which is not exactly unscathed given that he was the closest adviser to Gordon Brown during the “no return to boom and bust” years.
If he is right however, and the economy does sink back into recession, he can rightly take some credit. His admirers would suggest that at least he has staked out an original position.