I couldn’t remember putting peanuts in my knickers. Though as you get older you do have to keep an eye on yourself for eccentric behavior.

They’re back. There’s a mouse living behind my harmonium. But it’s my fault really. My domestic routines involve months of loafing about, throwing rags in corners and abandoning half-eaten cheese sandwiches in wardrobes, followed by 20 minutes’ frenzied tidying and scrubbing about three times a year.

Our kitchen dresser has probably stood against the wall for over 200 years, and all its cupboards are open at the back, forming a warren in which the mice can play. There’s a bin of peanuts for the birds in the outhouse, and it was when I found a stash of peanuts in my lingerie drawer that I began to smell a rat – I mean, a mouse. I couldn’t remember putting peanuts in my knickers. Though as you get older you do have to keep an eye on yourself for eccentric behavior.

There’s no argument about rats. Even Sir David Attenborough hates them. One shot out between his legs once when he was sitting on the lavatory. (I was a little shocked to discover that Sir David goes to the loo just like everybody else. Except the Queen.) As we live on a farm, the war on rats is an unavoidable necessity, but they’re mostly a problem outdoors.

Our terrier Patch is an enthusiastic ratter. But nowadays he only goes for very large rats. He seems to think that mice aren’t worth getting off the sofa for. When a wood mouse recently shot out from behind the harmonium and paused on the hearthstone, twitching its big round ears, he merely threw it a contemptuous glance and curled up even more comfortably on his velvet cushions.

The mouse stared at me, its eyes huge and dark and, I’m sorry to say, endearing. Only that morning I had begun to think that a mousetrap might become a necessity. The kitchen cupboards, where I keep my serving dishes, were showing unmistakable signs of mouse activity. (Do come to supper next week, by the way, and please excuse me if I burn the rice.)

I researched alternatives to mousetraps, and some new ideas caught my eye. One was an ultrasonic pest repeller. Another was peppermint oil. Apparently mice hate the smell of it. Oh, and there was another new idea, which was to clean the kitchen from top to bottom and close all food up tightly in plastic boxes.

It’s quite fun cleaning the kitchen from top to bottom if you haven’t done it for a couple of years. At least that’s what I told my trusty domestic help. She got down on her knees and scrubbed for England whilst I immersed cotton wool balls in peppermint oil and when that ran out, in clove oil. Now my kitchen smells like a dentist’s.

The pest repeller (made in China) arrived and I read the instructions eagerly. ‘Use the product indoor, wet place are forbidden to use’. If they can’t write correct English, how can I trust them to engineer a pest repeller emitting ‘superflow technology electromagnetic wave and ultrasonic wave’?

It’s plugged in and lit up, but as the ultrasonic waves are inaudible to the human ear, how do I know it’s working? We could be in an Emperor’s New Pest Repeller situation. Time will tell. Apparently if mice have a nest with young, they won’t move out for about a month, when the young ones are old enough to go to university.

Till then, if you come over and find me sprinkling peppermint oil behind the harmonium, you’ll know it’s not just to give a fresh, zingy whiff to Hymns Ancient and Modern.