"I have a door in the back of my wardrobe. It's there whenever I go looking for it.

"It used to be in the pantry, and then it was in the broom cupboard. It's been very good about positioning itself conveniently, really, over the years.

"Also, time at home stops for most people when they're here. So you needn't worry too terribly much about missing your . . . whatever kind of class you said it was. It will most likely be waiting when you go back."