“Did you know you use 22 calories to do a poo?”

I’M WALKING along a Cornish cliff-path. My brother, whose idea this was, is striding on legs as strong as Scottish cabers, half a field ahead.

I’m afraid that any minute now my brother’s going to about-face and make an announcement about “another lovely loop”.

My brother is a big, big fan of the everlasting loop. I’d be a big, big fan, too — I think, looking at his back — if I could actually walk, rather than stumble, which is all you can do when your brother sticks a pin in the map, says, “that looks nice” and streaks half a field ahead, leaving his children to weave in and out of your wellington boots like a zigzag running-stitch.

I’ve forgotten all about zigzag running-stitch. And how many questions young children ask. I’ve also forgotten the particular way these two phenomena combine so as to impede any kind of forward drive:

“Did you know that you use 22 calories to do a poo?” my niece, Whupass Talker, asks, jumping back and forth across my path.

“No,” I say, inching forwards in a syncopated totter.

“Yup,” she affirms, “I’ve got a book-mark [jump] which tells you all the calories you use to do different things [jump]: 22 calories to do a poo [jump] and…”

She breaks off as I fall over her younger sister, Running Stitch, whose footsteps have slalomed in and out of mine for 23 fields, and resumes while I scramble to my feet, “... 27 calories [jump] to brush your hair. Did you [jump] know?”

“No,” I pant, nursing my knee. “You can’t really say — categorically — that it takes 22 calories to do a poo, can you?” My nephew, whom I shall call Thesaurus, looks at me inquiringly as I smack into Running Stitch, who’s now punctuating her hairpin slaloms with abrupt and unexpected stoppages.

“You can’t, can you, aunty?” “Can’t you?” I gasp, grabbing hold of Running Stitch.

“No,” he says, “because it depends…” “On what?” I ask. “Well, for example, if you’re constipated, you’d use up more calories.”

He leaps in front of me and starts walking backwards, snail pace.

“Auntie?” “Yes?” I say, turning to Whupass Talker, who’s now walking on the backs of my feet. “Granny says that when you were at school, you were…” she shouts at my brother, half a field ahead, “WHAT WAS IT AGAIN, DAD?”

“WHAT WAS WHAT?”

“WHAT DID GRANNY SAY AUNTY WAS LIKE AT SCHOOL?”

“DISRUPTIVE,” he shouts back, marching in ease and comfort within the airy, sixty-foot exclusion zone that his caber legs have created.

“Were you disruptive?” Thesaurus asks, still walking backwards, snail-pace.

“Not by today’s standards.” “But were you?” “It’s not difficult to disrupt a convent.” “What do you mean?” “What does disruptive mean?” interrupts Running Stitch. She squeezes into the tiny gap between my feet and her backwards-walking brother, thereby causing a sudden obstruction. I careen left off the path. Staggering upright, I decide on impulse to break into a run.

“What are you doing?” they all shout. I canter back, brandishing a stick, swiping it left and right with a maniacal expression.

“This stick is about one metre long [whoosh]. I’ll answer all your questions if you stay outside its reach [whoosh], so that I can walk.”

They scatter immediately to just outside its reach. After which comes:

“Who was your worst teacher?” “Do you know the difference between fantasy and science fiction?”

“What does the word “coquette” mean?” “What’s your favourite flavour ice cream?” “Do you know how many calories you use when you eat a potato?”

“I have no idea how many calories you use to eat a potato,” I say [whoosh], “but on this walk, I’m using up a lot more calories than your dad [whoosh]… all things considered.”

“Why?” asks Whupass Talker. “Are calories real?” asks Running Stitch. “What do you mean, ‘all things considered’?” asks Thesaurus.