Carla Carlisle on late night intruders

Real writers rise early and put in a day's work when the rest of the world is still sleeping. I am not one. The words that occupy this piece of backyard real estate are strung together after midnight.

I feel a fraud because I don't keep farmers' hours or writers' hours. I don't even keep married hours. A communal breakfast usually means it's Christmas. Our separate routines work because we both think early-morning togetherness is overrated. The problems begin at night. I come alive just as he's ready for bed. That's when I head for my desk.

These solitary hours are a tranquil time and, on the few summery evenings we've had, I've worked with the windows open. I'd like to say that I've been listening to a concert of nightingales and barn owls, but that would be a lie. What I've been listening to is the sound of a truck coming up the back drive. Every night. Between 12:30am and 1am. Stopping like clockwork at the top of the farmyard by the hay barn next to the farm office.

At first, I thought it might be the keeper from a neighbouring farm out on fox control. Or perhaps the men doing late-night baling, but that's finished. I have to confess, I muttered the word ‘gypsies' more than once. When I first reported these nocturnal happenings to my husband, he urged me to wake him as soon as I heard the crunch of tyres on gravel. One night last week, I actually heard doors slam and voices. I ran to wake him. ‘Wait for me,' he ordered as I flew down the stairs, turning on the single working exterior light as I raced down to the barn. But they heard me. I saw the light in the cab as they jumped in, gravel flying as they sped off.

The row in the farmyard between husband and wife that followed would have terrified any trespassers with ill intent.

‘Why did you scare them off?' complained an irate man in his slippers. ‘These are not people you engage in conversation!' ‘I wanted to see their licence plate. To hear their voices.'

The farmyard security lights, triggered by the thieves who've been patiently casing the farmyard, blazed with a sodium glare that matched my fury.

The curious incident of the intruders in the night-time brought out our marital differences far more succinctly than our estranged sleeping patterns. I wanted to call the police. He didn't. I wanted to install CCTV cameras in the farmyard, the kind you can view on an app on your iPhone. He refused. As I was scanning eBay for landmines, he came up with a ludicrous plan. Next to where the truck stops each evening, in the open shed stacked with hay, he'd make a hide out of bales. His plan was to spy on the thieves from a peephole.

I said he was crazy. He said he'd contact the police when he had the licence plate. He went out after midnight, armed with a flashlight, his BlackBerry and a tumbler of whisky. I stayed inside listening while watching the Republican convention on C-Span. The governor of New Mexico was telling how, aged 18, she'd worked for her father's security firm guarding the parking lot at the Catholic church bingos, carrying a Smith and Wesson .357 magnum (laughter) that weighed more than she did (applause). Although I deplore the fact that no politician in America dares stand up to the gun lobby, I was on my way down to the gun safe to fetch the .22 when my husband returned.

‘Did they show up?' ‘Yes.' ‘Did you get their licence?' ‘I didn't need to. They come every night. About 1am. To deliver milk to the restaurant. They deliver milk to schools, offices, factories and restaurants all through the night.' I swallowed hard. ‘What did they say to you?' ‘They asked why I was up so late. They said I should be in bed.'