The Queen was showing the prime minister around the Royal Stables when one of the stallions close by farted so loudly it couldn’t be ignored.
“Oh dear, “said the Queen, “How embarrassing. I’m frightfully sorry about that. “
“It’s quite understandable, “said the prime minister, and after a moment added, “as a matter of fact I thought it was the horse. “
This joke is included in the Black Book of Jokes. You can order it from here.