They are telling this of Lord Beaverbrook and a visiting Yankee actress. In a game of hypothetical questions, Beaverbrook asked the lady: Would you live with a stranger if he paid you one million pounds? She said she would. And if be paid you five pounds? The irate lady fumed: Five pounds. What do you think I am? Beaverbrook replied: Weve already established that. Now we are trying to determine the degree. One version, attributed to many individuals.
I think I read it as ‘We’ve already determined what you are; now we’re just bargaining on the price’.
And every version is densely oblivious to the truth that (as the Bible points out in the story of Levi and Tamar) the sin of the customer is greater than that of the prostitute.
Viewed from a Judeo Christian perspective, every one of those jokes is a slam against some famous luminary. Not that they don’t necessarily deserve it.