Three weeks ago, on a cold and damp morning, I met the tortoise as I was crossing the garden between my office shed and the kitchen. He was making a concerted effort to get indoors, but found himself stuck halfway up the step, rocking gently on the fulcrum of the brick’s edge. His back legs were scrabbling to push his undercarriage far enough forward for his front legs to get some purchase, to no avail. As I approached, he fixed me with a severe look that said: your climate sucks, by the way.

“I’m not from here,” I said.

I knew his determination would eventually see him gain the step, and the one above it, because I once watched the whole grim process on a slow afternoon. But he would ultimately be defeated by the doorway’s overhanging threshold. I picked him up and set him on the kitchen floor.

“You’re welcome,” I said. He crawled under the dog’s bed, retracted his limbs and wound his neck in.

When the weather became more seasonable, he returned himself to the outdoors. I know from experience that approximately one in 10 of his attempts to descend the kitchen steps ends with him upside down, but he must have got it right this time.

His summer residence is a hollow under the garden wall, between a gnarled ivy root and the trunk of a cherry tree. He discovered it himself and made his own improvements, digging a little deeper to extend the space. That’s where he normally spends his nights, but on warm days he’s up before I am, and already well into his daily routine of destruction. I find him sunning himself on a patch of bare earth.

“Didn’t there used to be a big plant there?” I say. “What have you done?”

On Friday I see my wife striding across the garden towards my office. I change my computer screen to something that looks like work, but she stops halfway and turns.

“You bastard!” she says, bending over. She crouches over the bed and lifts the tortoise out of some foliage. Feathery green fronds hang from his chin. My wife carries him to the door of my office and holds him out, his four legs swiping at the air.

“You can’t just let him eat my things,” she says.

“I’m a businessman,” I say, typing. I do not mention that I just spent 20 minutes watching leaves dip and shudder as the tortoise tunnelled through the border directly towards the bush she bought from B&Q the day before, all the while thinking: how curious.

“I just planted that,” she says.

“Did you leave the price tag on it?” I say. “I think that’s how he knows.”

“It’s not funny,” she says.

“I gave him some lettuce this morning,” I say. “But he ignored it and ate the grass around it. He knows what he likes.” My wife turns the tortoise so it’s facing her.

“I’m going to trap you under the washing machine,” she says. The tortoise blinks and stares down at the ground with a look that says: like hell you will.

My wife fashions a makeshift prison from a clothes drying rack laid sideways across the entrance of the cupboard where the washing machine is. The next morning I see the tortoise staring at me through the vertical bars.

“It’s just until the new plants get established,” my wife says. In fact the arrangement only lasts until she needs the rack to dry some jumpers – the tortoise quickly makes his way under the oven, where he waits until the coast is clear. The next morning I hear the clunk from my desk as he tips over the kitchen threshold and his shell hits the brick step below. By the time I look up, he is gone.

“Where is he?” my wife says. I swivel round in my office chair to see her holding an annual of some description, still in its plastic pot, with little half moon bites taken out of the leaves.

“I ain’t seen him,” I say.

She storms over to the hollow beneath the cherry tree, but both the tortoise and I know full well that’s the first place she’d look.