When my youngest, Christopher, toddled out of nursery with the bearing of a cool-headed bomb disposal technician, concentrating deeply on the concaved plastic receptacle in his hands, I assumed he’d nicked it. Little kids are magpies, this one more than most. His pockets are museums to all manner of misappropriated treasures. It wasn’t until I got closer to him that I noticed a spider shuffling up and sliding down the bottom of the bowl, a pointless ritual undertaken beneath the disinterested gaze of its new God.

“He’s called Timmy,” Christopher told me.

“Hi Timmy,” I said.

“He’s big,” I said. And hairy. And kind of ‘hard’ looking. The sort of spider who’d walk up and punch you for looking at him funny.

Christopher is going through a creepy-crawly phase. Whether he’s just out of the shower or freshly donned in white or cream clothes, there’s nothing he likes better than to find a big mound of dirt and thrust as much of himself into it as possible, his hands retreating from that brown treasure chest laden with muck and worms and snails and woodlice. He’s like Steve Irwin meets Indiana Jones, a collector of living totems. Timmy belonged to Christopher now, whether he liked it or not. At least until Christopher got bored.

I’m not a great fan of spiders, but I hate flies with an even greater passion, so following the logic of the old proverb that ‘the enemy of my enemy is my friend’ I was content to regard Timmy as at least an acquaintance, if not exactly a pal.

Christopher carried that spider all the way home, never letting his gaze stray from it. When his older brother, Jack, met us coming out of his class he regarded the spider jealously, like it was a new 3D TV or a Playstation 5.

“Maybe check it out for a wee while then let it go in the garden,” I said. I left them in the house with their gran and aunty, then drove back to work. When I returned a few hours later the spider had been forgotten, by me as much as by the kids. That was a mistake. Like the bit in Jaws where everyone thought it was safe to go back into the water again – though I’m not suggesting for a second that sharks are anywhere near as terrifying as spiders. At least a shark won’t crawl across your face while you’re sleeping, or crawl up your toilet bowl to get up your bum.

I was in the kitchen cooking a stir-fry (the meal is irrelevant, I just wanted there to be documentary evidence that a) I cooked occasionally, and b) I didn’t just eat pizzas all the time) when I heard an almighty scream from the living room. Screams are so ubiquitous in my house that they’re almost a background thrum, like the low-level buzz of the TV or the clinky-gur-gur of the fridge, so I hot-footed rather than fled to the living room. Chris is a clumsy wee fella and I reasoned he’d probably mis-timed a daredevil stunt betwixt foot-rest and couch, or simply suddenly and randomly tripped over his own feet, as he’s prone to do.

“What happened?” I asked my mum as I moved in to wrest him from his granny and wrap my arms around the red-faced little cherub.

“Bloody thing bit him,” said my mum.

“What bit him?” I asked incredulously, forgetting that the spider had ever existed, my brain refusing to even consider it as a suspect. It’s like if you were in a house with two men and a penguin, and you walked into the room, and one of the men was lying dead on the floor and the other man turned to you and said: ‘It bloody killed him!’ You’d whirl your head around 360 degrees looking for a human assailant, even if you clocked the penguin standing at your feet clutching a bloodied knife and shouting ‘I’LL KILL AGAIN! I’LL KILL THEM ALL!’ before laughing maniacally.

“Penguin!” you’d shout. “Do you know who did this?”

A spider bit him? Really? Sure, it was a tough-looking spider, but surely it wasn’t ‘pick-a-fight-with-a-tiny-giant’ tough? It was still a garden spider… wasn’t it? Oh please God let it be a garden spider, and not some diminutive banana-box refugee from the Isle of Biteos, somewhere off the Dominican coast.

“It latched on to his finger and he had to shake it a few times to get it off,” said my mum, shock and concern impaling her words.

Timmy was standing nonchalantly, nay, defiantly, on the floor in the centre of the room. I upturned the receptacle he’d arrived in and placed it over him like a Perspex prison. I could imagine him in there giving himself makeshift tattoos with a match-stick, and playing eight harmonicas at once.

The tip of Christopher’s index finger was swollen. He cried for a few minutes, but managed, through his huffing sobs, to ask if he was going to turn into Spiderman. I knew I had to keep the spider until I could be certain it was a benign specimen, and Christopher wasn’t going to have a bad reaction to its bite. But I had to let my little lad know that justice would be done, and would be as swift as it was brutal.

“No-one bites my little boy,” I told Christopher, as he cuddled into his gran. He looked up at me with a grimly serious face. “I’m going to splat it for what it did to you. Does that sound good?”

He locked eyes with me, and gave a grave, mob boss’s nod. Timmy’s fate was sealed. Eight concrete boots coming up. The perspex prison in which the condemned arachnid languished had been upgraded from Super-Max to Death Row.

Thankfully, hours later, Christopher seemed to be suffering no ill effects, beyond a sudden reappraisal of his relationship to spiders. Even still, I phoned the NHS for advice, and courted public opinion on Facebook (which ranged from ‘He’ll be fine’ to ‘I’m not being funny, but a house spider bit me once and my tits and legs fell off and a piece of my spleen exploded’). And all the while Timmy sat there, alone, trapped, perhaps as a fly priest buzzed by and read him his last rites through the plastic.

But Timmy was lucky to have bitten a merciful human. The little spider’s stay of execution came as I was cuddling Christopher in his bed, trying to coax him to sleep with the usual mixture of soothing and seething.

“I don’t think we should kill the spider, daddy,” he said thoughtfully. “I’m bigger than him and maybe he thought I was going to kill him.”

I nodded. “Then I’ll let him go. And he can start a new life somewhere else.”

“Maybe get a wife,” he said.

“Now, come on, Christopher, don’t wish that on him. I thought we were being merciful. We’d be better off killing him.”

OK, I didn’t say that last part.

After he’d gone to sleep I paid a visit to Timmy. I lifted the lid of his prison a crack and slid a few pieces of cucumber and a tiny crumb of chicken nugget in next to him.

“You’re lucky this wasn’t your last meal, you eight-legged dick,” I told Timmy. He just sort of stared at me. I could’ve sworn he said something about fava beans and a nice chianti, but maybe I just imagined it.

All things considered?

I think we should get a tarantula.