When Warren Buffett was interviewed on CNBC last week about Unilever’s rejection of a bid from Kraft, he told a funny story. Or rather, he told a story he thought funny. He looked at the young woman doing the interview and asked if she knew the difference between a diplomat and a lady. No, Becky Quick replied.

Eyes twinkling with amusement, Mr Buffett proceeded to tell her that if a diplomat says maybe, he means no. But “if a lady says no, she means maybe. And if she says maybe, she means yes. And if she says yes” — at this point Mr Buffett’s eyes disappeared into his grinning face — “she’s no lady!”

The camera angle broadened to take in the face of the interviewer, who was staring at him in horror with her mouth locked into a smile. The joke was not funny. Even in the universe of unfunny sexist jokes this one was particularly crass.