So here’s what happens. I am sitting down to dinner with Harriet, 5. Suddenly, and quite without warning, just as my  spoonful of food is heading for blissful oblivion,comes the question.

“Daddy?”

“Yes sweetheart?”

“Where does poo come from?”

Now any sensible father would have done what men have done since time immemorial (“Ask your mum”) but oh no, not me, I just waded straight in with both feet. After all, I reasoned, if they’re old enough to ask, they’re old enough to know.

Unless they ask about sex, of course. In which case it’s definitely time to ask your mother...

“Well, it’s like this” I began, suddenly not enjoying my meal quite as much. “When you eat food like this, your stomach breaks it down into things it can use to help it work and grow, and things that it doesn’t need. It gets rid of the bits it doesn’t need by pushing them out of your bottom and into the toilet.”

I am feeling pretty proud of myself at this point for what Ithought was a pretty good answer. I notice that Mrs Bad Dad and oldest offspring are steadfastly avoiding any eye-contact whatsoever, and this is, I feel, on balance, probably a good thing.

“Is that OK?” I ask, curious as to whether I have over or underplayed the Biology lesson.

“I see”, she replies thoughtfully, apparently satisfied with my answer.

“Anything else you want to know?” I ask, encouraged.

Her reply drains the colour from my face, possibly for all time.

“Yes – so where does Tigger come from then?”