Did Churchill say he would drink poison tea if he was married to a particular person?

Question

The following quote is very frequently attributed to Churchill responding to Lady Astor:

Lady Astor: If you were my husband, I’d poison your tea.

PM Churchill: Madame, if you were my wife, I’d drink it.

I've seen this quote constantly over the years, and its been making the rounds again across reddit. It seems to me that Churchill didn't say it because it feels like one of those too good to be true quotes that is usually false. Some mention that its misattributed to Churchill or he was referring to another person, but rarely are there any sources in those comments.

Did Churchill say: "Madame, if you were my wife, I’d drink it"?

Answer 1

According to Quote Investigator, the following joke was published in the Oswego Daily Times on 18 November 1899.

The “Listener” reports the following from the subway: On one of the recent warm days a sour-visaged, fussy lady got on one of the smoking seats on an open car in the subway.

Next her sat a man who was smoking a cigar. More than that, the lady, sniffing, easily made out that the man had been eating onions. Still more than that, she had the strongest kind of suspicion that he had been drinking beer. The lady fussed and wriggled, and grew angrier, and looked at the man scornfully. Presently she could endure it no longer. She looked squarely at him and said:

“If you were my husband, sir, I’d give you a dose of poison!”

The man looked at her. “If I were your husband,” said he, “I’d take it!”

There are many other citations after that on the Quote Investigator page.

Churchill first became Prime Minister in 1940, and Lady Astor moved to England around 1905, so it seems very unlikely that they would have had this conversation prior to 1899. If they did have such an exchange in later years, they certainly can't claim original credit for the witty remarks.