Late in my life I have become the owner of a house with a garden. But there are very few gardens in the area of the inner city where I live and naturally my garden has become a focus of envy from the deserving poor.

Last Sunday I was in my garden, drinking fine champagne from the bottle and playing croquet on the lawn with my pantalooned children, when I began to notice some of the people with no gardens from other less salubrious parts of the borough straddling my fence. They were probably jealous of my lawn and flowerbeds, and wished they could have them, which they can’t because they are mine and I must deserve them otherwise why would they have come into my possession?

I squirted the grasping interlopers in their puzzled faces with greenfly spray and then poked them off the fence with a hoe, sending them tumbling down into the fly-tipped mattresses and old nappies below in the council flats’ parking area. Then I went off to smash up some champagne bottles so I could fix broken glass to the top of the fence, in order to lacerate off the interlopers’ buttocks and genitals should they try to climb the fence again, the vile cockroaches. A newt lives below the steps up to the house. I am kind to it.

Later in the day I became aware that the North London Hang Gliding Club were holding their monthly glidepast in the sky above my garden, with the usual and inevitable consequences. Soon the bodies began falling, the mortal shells of poor misguided souls who mistakenly hoped they could find their way into my garden from the air, and had clung to the glider wings, like kittens gone viral on Twitter, but not cute enough to earn their own hashtags.

Illustration by David Foldvari

Luckily, I had already taken the precaution of suspending cricket nets from the tree branches that hang over the garden to catch the falling corpses, which I then threw into the compost to decompose out of sight. My neighbour, who is Australian, has taken to bribing the glider pilots to have their flying fun further south, so that any stowaways make their fatal final landfall in the nearby boroughs of Islington or Camden, rather than onto our immaculate lawns, solving the immediate problem.

At around teatime I was wearing small tight white tennis shorts and drinking champagne again, while playing swingball with a TV producer friend from the media, when I heard a noise coming from the old sewer below the patio. The ongoing escalation of these constant interruptions, all in one afternoon remember, was rapidly becoming tiresome.

Handing Alan my champagne and racket, and crouching down on my bare knees by the manhole cover, I heard a voice say, “Please can we come in your garden? We haven’t got a garden where we live.” And I said, “No, get back in that sewer, you no garden people. I’m very sorry that you haven’t got a garden but this is my garden and I deserve it.” And I walked away. But the tapping continued.

I listened again. “Please, it’s really horrible in the sewer. We’ve been crawling through it for days. And back at the other end of it there’s no food and a man trying to behead us.” This changed things, I suppose. A straightforward narrative based on simple avaricious envy of my garden had been complicated to encompass a basic human desire for survival, a trickier thing to dismiss out of hand.

But as I considered the problem, the manhole lid started coming off. Luckily, I managed to force the woman beneath it back down into the sewer, kicking her in the face and punching her. And then I slammed the cover back down, at least buying myself a little more time to ponder the moral dilemma her plea had posited.

Then, still wrapped in thought, I put a really big flowerpot on the manhole cover so that she and the other people without gardens couldn’t get into my garden through their hole. This solved the problem to an extent. They still hadn’t got gardens but at least they weren’t in my garden. They were trapped in a sewer underneath my garden, dying, which was better I think. And also, their deaths would hopefully deter any other people without gardens from trying to come through the sewer into my garden, which they can’t, because it’s mine.

I wondered if it was really humane to have people trapped in a sewer and dying just for trying to get into your garden. Then it came to me. The real cruelty lay in my allowing people to go into the sewer in the first place. So I found an old drainage plan on the internet, noting that the sewer surfaced somewhere out on Hackney Marshes, which had recently been occupied by a sadistic fascist death cult hellbent on the murder of anyone they disagreed with even remotely, which was unfortunate, but hardly my fault.

I got into the armoured 4×4 I use for the school run, and drove round to the sewer opening, where the people without gardens were getting in, and poured petrol all over it and blew it up in a massive explosion, so that all the people without gardens who had been going into the sewer could stay where they were and die there from being starved and beheaded, like they were supposed to, rather than dying in a sewer on the way into my garden which is mine.

And then I thought, if only there were something I could do to make the whole world fairer so that the people trying to get into my garden didn’t feel the need to try and get into my garden in the first place. But there just isn’t I suppose.

And so I laze in my garden, champagne glass in hand, the bubbles popping in the sun, as the fence wobbles and buckles, and bodies block out the light as they tumble into the cricket nets, and the manhole cover over the sewer rumbles and grumbles. Later I will raise the fence an inch or so and stick more glass on the top of it, and roll another old flowerpot over the manhole cover. And before bed I will tighten the nets once more and empty the day’s catch into the compost. But for now, I will swing here in my hammock, sipping my champagne, and sniffing my freshly-mowed lawn in the dying of the midsummer day.

Stewart Lee is curating the All Tomorrow’s Parties festival in April 2016, and A Room with a Stew is playing Edinburgh and London.