A piercing aroma of decomposing rodents oozes through the floorboards

The wildlife in this corner of north London is surprisingly rich and varied. There are cats, of course, and any number of dogs, several of them taken for walkies by professional dog walkers, whose services seem to become more popular by the day. Up on the disused railway line, which is now a slightly scruffy nature reserve, you can see shrews and field voles and even the occasional deer, by all accounts, as well as a few estate agents who have gone feral and made homes in the undergrowth.

Joggers run and wheeze and sweat dangerously, and at the weekend furious men cycle up and down the path, followed by cowed children on tiny bikes doing their best to keep up. Birds are plentiful, and sing their delightful songs of hunger and sexual desire at any time from five in the morning, every day of the year.

And at night, when even teenagers have gone to sleep, the foxes come out to play. A dozen years ago, when my boy was an unusually colicky baby, I took him out in the sling at three in the morning to walk the streets until the little bleeder finally consented to nod off. It was a hot summer night, and in my 75 minutes or so tramping the pavements, I saw one other person, two cars driving past and three foxes. They own the area. We merely lease it from them.

The foxes, I presume, are indirectly responsible for all those signs pinned to trees by the owners of lost cats. The better-fed and more mollycoddled the cat, the easier it must be for Foxy to catch, and the more satisfying repast it must make. This change in the food chain seems to have made life much easier for the mice. Up on the disused railway line, there must be constant threat to their nibbling, scurrying way of life, but in the basements of these houses there is none at all. My neighbour downstairs can hear them all the time. They squeak, they scamper and, their absolute speciality, they reproduce. They are like mobile tribbles.

My neighbour is a kind man and not keen on traps or poison, so on occasion he has borrowed our half-witted cat for clean-up duties. It's not entirely effective. Our cat is huge and well-formed, but he is also a wuss of the first order, who hides under the sofa when a lorry drives past and only ventures down his specially constructed cat ladder to the garden below when it's dark, dry, warm and quiet. He prefers staying indoors and eating. He also likes standing guard at night, in case a mouse should lose its way and climb into our flat by mistake. On the rare occasion that he manages to catch one, we always know because his poo has a tail in it.

Since Christmas, though, decisive action has been taken, and I think it's our new neighbour next door who has taken it. I have met him only once, but he is German and has the neatest back garden I have ever seen. My guess is that he has laid down industrial quantities of poison, and the piercing aroma of decomposing rodents oozing through our floorboards suggests that they are coming next door to die. It's mass mouse murder down there. You can feel the smell at the back of your throat. Not that I'm complaining: I favour humans over mice every time. Meanwhile, the half-witted cat has stopped standing guard, and sits complacently, as though it's all his doing. He must think we're idiots, and given how much he costs to feed, he's probably right.