Just before Christmas our cat Runty died and I wasn’t in any rush to find a replacement. I like cats well enough but I wouldn’t consider them one of life’s essentials. You can’t ride them; they won’t come with you on walks or bark at burglars or gaze at you like you’re the most wonderful, special, adorable person in the entire universe; plus, of course, they are the most evil, deadly and inappropriate predator.

Domestic cats kill an estimated 55 million birds each year in the UK alone — and an estimated total (when you add in all the mice, voles, slow-worms, newts and so on) of 275 million wild animals. When you live close to nature, as we do in the country, you see what a terrible struggle it is for animals just to stay alive under normal conditions. Introducing a moggy to your local ecosystem seems an act of wanton vandalism: like letting a hungry lion into a school playground. And to what end, exactly? Just so you can satisfy your pathetic need to have a creature that goes ‘purr purr’ occasionally when it deigns to allow you to let it lie on your lap and be stroked?

When I put my no-cat proposal to the family, however, I got short shrift. ‘I’ve had a cat in my home every year of my life since I was a child. Good luck with your stupid no-cat rule,’ said the Fawn, haughtily. ‘We’re getting a kitten. I’ve never had a kitten. There is no way we’re not getting a kitten,’ said Girl.

Then fate intervened in the form of Ernie, who is lying curled up next to me as I write, dark and soft and caressable as a gigantic mink hat. As soon as I saw Ernie, I fell in love with him. He originally belonged to a friend whose wife had intended Ernie to be part of her pet-therapy business. But the business never took off and the friend needed to shed a few cats. ‘Would you like him? He needs a good home.’

Ernie is like no cat I’ve ever encountered before. He’s a pedigree breed — I won’t say which but ailurophiles will probably be able to guess — and he looks more like a miniature panther than a cat. His paws are huge; he has enormous, orange, owl-like eyes with pupils the size of a black hole; his body is a chunky oblong with well-defined musculature, which meets in a V-shape cleft behind a neck so thick it’s more like an extension of his broad, fat-cheeked head.

When you pick him up, he feels like the embodiment of the word ‘heft’. He’s so big, you can hear him coming a mile off — thump, thump, thump on his giant’s paws. At first, I’d wondered how our friend could possibly have wanted to give away so magnificent a creature. But that was before I saw just how much the beast consumed: two types of top-of-the-range cat food at £18 for a small bag, mixed to the gourmet prince’s satisfaction.

Normally, when a feline enters a new home it goes through a period of nervous acclimatisation. This is especially true when, as in our case, there is a resident dog hell-bent on chasing it and, ideally, eating it. Poor Runty always had to be on her guard against our naughty spaniel Daisy. But right from the start, Ernie showed himself sublimely indifferent to the canine threat. This was Ernie’s manor, now, and the wretched dog would just have to live with it.

Admittedly, it did help having the Rat over from Hong Kong. Having watched the entire TV oeuvre of the American dog whisperer Cesar Millan, Rat knew exactly what to do: expose the spaniel regularly to the cat’s arse. Each morning, Rat would approach Daisy’s basket, holding the cat so that its hind quarters pointed to Daisy’s questing nose, knee forward protectively to ward off any snapping lunges. Daisy and Ernie aren’t exactly friends, yet. But they do at least treat one another with wary respect. Well, Daisy does. Ernie just doesn’t give a damn.

It ought to be really irritating, Ernie’s weapons-grade sense of entitlement. He’s like The Tiger Who Came to Tea. He struts round the house, noisily demanding attention, doing all the things that used to infuriate me when his predecessors tried it on: licking the butter dish, breaking into packets of bread or ham or cling-film wrapped sandwiches, rolling on the bed (spreading fleas, probably), shitting in the bath. I’d like to get cross but he does it with such insouciance and such professionalism you cannot but admire his technique. The way, for example, he’s so expert at sussing out your cereal bowl while pretending that it’s the last thing on his mind, lulling you into a false sense of security, pouncing the moment your attention drops. Yes I know all cats can do this to a degree, but not with Ernie’s style and class. Everything about him screams alpha predator.

It’s not just me, either. Everyone feels this way, including Girl, who swore blind she would hate any new cat that wasn’t a kitten but was instantly smitten with the grown-up Ernie. I’ve lost count of the number of visitors who’ve told us: ‘I’ve never been a cat person. But that one of yours…’

I don’t want to become a cat person myself. Conservatives are horse people and dog people. Cat people tend to swing left, perhaps because unlike conservatives they find nothing wrong with lazy, vicious, sly, scheming, ungrateful, flea-ridden spongers draining the household budget as if the world owed them a living. Ernie, though, is sorely testing my resolve. If only I can somehow train him to accompany me on my morning run and jump a post and rails, the hapless spaniel’s days may be numbered.