Q:

"It is a catchphrase sometimes claimed to date to 1887, when British Prime Minister Robert Cecil, Lord Salisbury decided to appoint Arthur Balfour to the prestigious and sensitive post of Chief Secretary for Ireland. Lord Salisbury was Arthur Balfour's uncle. The difficulty with that proposed explanation is that there is no contemporary documentation for it, and, despite extensive searching, the earliest known published uses of the phrase are two from 1937 and two from 1938 (these and other quotations at American Dialect Society list archived posts by Stephen Goranson)."

From Wikipedia