When Timmy complained of hearing noises at night we dismissed them as the house settling into its foundations. When he claimed he saw strange people skulking in the corners of his room we dismissed them as figments of his over-active imagination. It wasn't until it was too late that we realised we should have paid more heed to what he’d been saying.

Getting Timmy off to sleep each night had always been a chore. Even as a very small child it had been difficult to get him to drift off and he had always been a restless sleeper, awoken by even the slightest sound. We thought he would grow out of these problems as he got older but things actually became worse. A couple of times a week we’d be dragged from our sleep by his screams as he suffered another nightmare. You’d have to sit with him for hours on end before he finally drifted back off to sleep; we would regularly turn up for work unfit for service as a result.

After he turned seven he began having recurring bad dreams. In them he could hear footsteps from above, as if there was some unthinkable horror crawling the ceiling of his room. On other occasions he would catch a glimpse of a figure observing him from the darkness behind his wardrobe. We tried our best to explain these incidents away. Our house was old. Creaks and groans were common and only natural. There couldn't possibly be anyone else in the house, all of the windows and doors were locked tight. There certainly are no such things as ghosts. But Timmy never bought our explanations.

We bought him a nightlight and for a while this did the trick. We believed the light had banished these apparitions back to the prison of his mind. We had a week of blissfully unbroken sleep and believed a corner had finally been turned. But one night the visions started again with a vengeance.

I would be lying if I said that Timmy’s actions hadn't been a nuisance. They caused a great deal of strife for me and the wife; we fought a lot and struggled at work. This was caused by a mixture of exhaustion and frustration. We even snapped at Timmy, telling him he was becoming a big boy now and needed to grow up. Those harsh words fill me with shame now, after what happened. If only we had taken him more seriously, this would never have happened.

The night everything happened was no different from any of the others. We were awoken by Timmy’s screams and I stamped angrily into his room. I shouted at him, I admit it, demanded that he be quiet and let his parents get some deserved rest. He quietened down somewhat and I left him in his room with the light on. From my bed I listened as he fought valiantly to quieten his sobs. I was already feeling guilty for raising my voice but I didn't allow myself to go back to him to apologise. Eventually the blubbering ceased and I took that to mean that Timmy had fallen asleep. I was so exhausted that within minutes I had drifted off myself.

The wife always got up earlier than me to prepare Timmy’s breakfast and get him ready for school. She would always wake me as she stepped out of bed so I was already awake when I heard her scream. I jumped from the bed and dashed to Timmy’s room where the sound had emanated. I couldn't believe what I was seeing. Timmy’s bed was empty.

We searched the house quickly to see if Timmy was hiding from us. Sometimes he would do this to punish us if we were too strict with him. But we couldn't find him in any of his favourite spots. We checked the windows and doors, fearing he had run away from home, but they all remained locked. In a panic, we called the police.

As I paced the house aimlessly waiting for them to arrive I happened to notice the loft hatch was ajar. Irrational relief washed over me; despite the fact it was impossible for him to have gotten up there by himself, that must be where he was hiding. I grabbed the ladders from the garage and made my way into the loft, speaking soothingly to Timmy the whole time. What I found up there was the most terrible surprise I could ever have imagined.

There was clear evidence of habitation. Behind a stack of boxes filled with our junk I found two dirty sleeping bags placed upon mattresses made of soiled rags and assorted belongings pilfered from the packages up there. By the sides of the beds were a number of open food cans, some knives and forks. A small pile of dirty clothing stood at the foot of one of the beds. To my growing horror I noticed two shafts of light coming from small holes in the floor of the loft. In a daze I lowered myself and confirmed my suspicions; they allowed a perfect view into Timmy’s room. I was physically sick at that moment. People had taken residence in our home without us knowing and what Timmy had been saying was true. He had actually seen and heard the things we had denied.

The one thing I keep asking myself is how had those vagrants or squatters, or whatever you want to call them, lived up there for so long without us noticing? It repulses me to think how long they had been up there and how much they had seen. I hate them for what they have done but I hate myself more for not taking my boy’s problems more seriously. I was wrong to dismiss his claims as childish nonsense. I've since come to realise that not all horrors are supernatural; the majority of them are flesh and blood. I’ll never forgive myself for not realising earlier.