The grammar has a rule absurd
Which I would call an outworn myth:
A preposition is a word
You mustn't end a sentence with!
— Berton Braley

quote:

I checked the indexes of a dozen Churchill biographies, but none of them had an entry for “prepositions.”


Ben Zimmer has presented evidence on the alt.usage.english list that this story was not originally attributed to Churchill at all, but to an anonymous official in an article in The Strand magazine. Since Churchill often contributed to The Strand, Zimmer argues, it would certainly have identified him if he had been the official in question. It is not clear how the anecdote came to be attributed to Churchill by Gowers, but it seems to have circulated independently earlier.