Each big inflation -- whether the early 1920s in Germany, or the Korean and Vietnam wars in the US -- starts with a passive expansion of the quantity [of] money. This sits inert for a surprisingly long time. Asset prices may go up, but latent price inflation is disguised.
The effect is much like lighter fuel on a camp fire before the match is struck.
People’s willingness to hold money can change suddenly for a "psychological and spontaneous reason", causing a spike in the velocity of money. It can occur at lightning speed, over a few weeks. The shift invariably catches economists by surprise. They wait too long to drain the excess money.
"Velocity took an almost right-angle turn upward in the summer of 1922," said Mr O Parsson. Reichsbank officials were baffled. They could not fathom why the German people had started to behave differently almost two years after the bank had already boosted the money supply. He contends that public patience snapped abruptly once people lost trust and began to "smell a government rat".
Some might smile at the Bank of England "surprise" at the recent the jump in Brtiish inflation. Across the Atlantic, Fed critics say the rise in the US monetary base from $871bn to $2,024bn in just two years is an incendiary pyre that will ignite as soon as US money velocity returns to normal.