A Lingua Franca post by Ben Yagoda takes off from a 1965 remark by Robert Manry, a copy editor for the Cleveland Plain Dealer: “I told myself that if most of the days ahead were as pleasant as this, our trip would be a breeze, or, as the English say, a piece of cake.” Yagoda, like me, was surprised by the attribution to the English, and investigated, finding that it began as RAF slang, the first quote in the Google Books database coming from a 1942 Life magazine article written by an RAF pilot: “It sounds incredible considering that we were 150 miles from the target but the fires were so great that it was a piece of cake to find the target area.” He has an Ngram chart showing US usage overtaking UK in the 1970s, and ends with this anecdote:
There’s a coda to the tale of a piece of cake. Fans of Roald Dahl may recognize it as the title of one of his short stories, included in his 1946 collection Over to You: Ten Stories of Flyers and Flying. That story is actually an extensive reworking of his first published work, an article in the August 1942 edition of The Saturday Evening Post called “Shot Down Over Libya.” In the piece, labeled a “factual report,” Dahl talks about being given the assignment, in 1940, to bomb a group of Italian trucks in the Libyan desert. One of his fellow flyers remarks, “Hell’s bells, what a piece of cake!” Another agrees, “What a piece of cake.” (This is retroactive evidence of an earlier British use of the expression than given in the OED, but can’t be included in the dictionary as such since the publication date is 1942.)
Do my UK readers now think of this as an Americanism, or does it still retain a whiff of its raffish RAF origins?