No one knows for sure where this expression came from originally, but a popular theory is that it derives from an incident in 1887 when Conservative British Prime Minister Robert "Bob" Cecil, in a brazen act of nepotism, appointed his own nephew Arthur Balfour to a plum posting as Chief Secretary for Ireland. This move was surprising and received widespread condemnation, given that Balfour's only relevant qualification seemed to be that Bob was his uncle.