Upstairs at the White House in my sister S’s room, the cocker spaniel puppy would not let go of my hand. His alligator teeth were well and truly clamped into my skin. I really had to shake him off before he did any damage.

Then I struck on an idea. What if I just ignored him? I stopped paying him and attention and within seconds C decided that I wasn’t worth bothering with after all.

I was now free to make a visit to the upstairs lavatory unaccompanied by a dog.