Language Log

The earliest citation of the story that I've found so far in newspaper databases is from 1942, without any reference to Churchill:

The Wall Street Journal, 30 Sep 1942 ("Pepper and Salt"): When a memorandum passed round a certain Government department, one young pedant scribbled a postscript drawing attention to the fact that the sentence ended with a preposition, which caused the original writer to circulate another memorandum complaining that the anonymous postscript was "offensive impertinence, up with which I will not put." —The Strand Magazine.

Churchill often contributed to London's Strand Magazine, so it seems unlikely that the magazine would fail to identify the unnamed writer as Churchill if he were indeed the source of the story. Attributions to Churchill only began to surface well after the war's end. The usual source of the Churchill attribution is Sir Ernest Gowers' Plain Words (1948):

( http://www.ourcivilisation.com/smartboard/shop/gowerse/chap9.htm) It is said that Mr. Winston Churchill once made this marginal comment against a sentence that clumsily avoided a prepositional ending: "This is the sort of English up with which I will not put".

Though Gowers is typically the only source cited for the attribution (as in The Oxford Dictionary of Quotations and The Oxford Companion to the English Language), the Churchill story was circulating in 1948 in various forms. Here is the earliest reference I've found:

'Up With Which I Will Not Put' Is Latest Winston Churchillism Portland (Maine) Press Herald, 20 Mar 1948 London March 19 (UP) -- Another Churchillism has been read into the record -- "up with which I will not put." Thursday night in the House of Commons, Glenvil Hall, financial secretary to the treasury, made a plea for clearer English. He cited as an example of Winston Churchill's "forceful if not always grammatical English" this marginal notation that the wartime Prime Minister scribbled on a document: "This is nonsense up with which I will not put."

This same wire story appeared later in March '48 in another newspaper — the Daily Gleaner of Kingston, Jamaica — so clearly the anecdote was traveling far and wide. By December of that year, a more embellished version was circulating:

The Wall Street Journal, 9 Dec 1948 ("Pepper and Salt") The carping critic who can criticize the inartistic angle of the firemen's hose while they are attempting to put out the fire, has his counterpart in a nameless individual in the British Foreign Office who once found fault with a projected speech by Winston Churchill. It was in the most tragic days of World War II, when the life of Britain, nay, of all Europe, hung in the balance. Churchill prepared a highly important speech to deliver in Parliament, and, as a matter of custom, submitted an advanced draft to the Foreign Office for comment. Back came the speech with no word save a notation that one of the sentences ended with a preposition, and an indication where the error should be eliminated. To this suggestion, the Prime Minister replied with the following note: "This is the type of arrant pedantry up with which I will not put."

Over the following years, other variations circulated in the newspapers, all featuring Churchill. (By the time a reader inquired after the Churchill anecdote in The New York Times's "Queries and Answers" section in 1951, "countless readers" sent in versions of the story, but none had an authoritative citation.) Some later versions feature an officious book editor rather than a Foreign Office clerk. (A review of the variations can be found at: http://www.wsu.edu/~brians/errors/churchill.html.)

Further research into the Churchill attribution would require searching the House of Commons archives to track down exactly what Glenvil Hall said in March 1948. I'm guessing he embellished the story along the lines of later attested versions. It appears, however, that the anecdote emerged during WWII featuring a generic memorandum writer, and only after the war did the story get attached to Churchill (as so many other anecdotes have).

—Ben Zimmer