Did anyone tell you about the day when David Cameron was visiting a primary school in England, and was taken into the room of a class discussing words and their meanings.
The teacher asked David Cameron whether he would care to lead a discussion on the word "Tragedy", so he asked the class to give him an example.
A little boy stood up, and said, "If my best friend, who lives on a farm, was playing in the field, and a tractor ran over him, and killed him, that would be a tragedy".
"No," said David Cameron, 'that wouldn't be a tragedy: that would be an accident".
A little girl raised her hand: "If the school bus had fifty boys and girls in it, and it drove over a cliff, killing everyone inside, that would be a tragedy".
"I'm afraid not," explained David Cameron; "That is what we would call a great loss."
The room went silent. No child volunteered.
David Cameron's eyes searched the room. "Can no one here give me an example of a tragedy?"
At the back of the room, a little hand went up, and a quiet voice said, "If a plane carrying you and Nick Clegg was struck by friendly fire and blown to smithereens, that would be a tragedy".
"Magnificent!" exclaimed David Cameron, "That's right! And can you tell me why that would be tragedy?"
"Well," said the quiet voice, "It has to be a tragedy, because it certainly wouldn't be a great loss, and it probably wouldn't be an accident."