In a turn of phrase which I think many Keynesians today might feel would have been better left unsaid, Keynes argued that this would work even if workers were hired by the government simply to dig holes in the ground and fill them up again.
In fact Ileft the Radio Wales studio early yesterday rather aware that if Owen Smith didn't turn out to be Ed Miliband's choice, I had rather a lot of ground to make up with whoever had been favoured.