“I must do it. But I fear to do it. Upon my soul I do.” So said Alec Guinness’ King Faisal to Peter O’Toole’s Lawrence in Lawrence of Arabia when faced with demands that he place his Bedouin fighters under British command. And so in effect said Federal Reserve chairwoman Janet Yellen to the Economic Club of New York when faced with the prospect of raising interest rates by a full percentage point in four steps this year, as she previously quasi-promised – “not a plan set in stone”. She is right on both counts: She must end the distorting effect of near-zero interest rates, and it is reasonable to fear to do it.

Yellen finds herself a dove increasingly faced with the need to don the feathers and attitude of a hawk. She flirted with such a metamorphosis in December, when the Fed’s monetary policy committee raised rates by 0.25 percent, and indicated it would institute similar increases three more times this year, a program now “evolved” into wait-and-see.