Ian McMillan: A crunch decision in the middle of the night

I've got no idea what time it is, but somewhere somebody is revving up a miniature motorbike, or an eagle is clearing its throat, or somebody up the street is scraping wallpaper, or a giant pickle jar is being unscrewed with great difficulty.

In other words, there's a noise. A late-night sleep-cracking noise. In the past, I've read about people who were kept awake by a hum, a

persistent early-hours throbbing that just wouldn't let you rest; I remember hearing a radio programme years ago about The Bristol Hum, a just-within-hearing buzz that disturbed a number of people in that fair city.

There was never really an explanation: it could have been UFOs, or underground experiments, or overhead wires, or planes coming down to Bristol Airport or, let's face it, a giant pickle jar being unscrewed with great difficulty.

My noise isn't a hum, though, or a buzz or a rattle. It's a crunching, or a chewing, or a couple of cogs grinding in a machine somewhere on the main road.

Night amplifies noise, of course. Perhaps as you sleep your ears grow bigger and then when you wake up they shrink back to their normal size; this would explain why old men, who don't need much sleep, have ears as big as rhubarb leaves. Years ago, we went on a family holiday to

Brittany and we stayed in a set of tents on a site that had a kids' club, a giant chess set and a bar that sold lovely cold bottles of

golden French beer, so it was perfect.

One night, though, as my wife and kids slept, I was woken up by the

sound of a monster in the room, moving around the canvas floor on monstrous feet. It must have been a wolf, a giant wolf, a wolf bigger than any wolf that had ever lived; it had gorged mightily on the giant chess set and now it was coming for the McMillans. Or that's how it felt. I woke my wife up and we sat and listened. It was in the early 1990s but I can still recall the fear: sweat trickled down my back and the hairs really did stand up on the back of my neck, something I thought only happened in films or comics.

I reached for a torch and switched it on: a hedgehog the size of a

minibus (I'm exaggerating, but only slightly: it was the size of an Aga) was snuffling around. After much debate between me and my wife, I got up and swept the hedgehog from the tent with a brush. I pushed it down the path past the tent of an elderly German who was still up at that time, gazing at the stars. We nodded to each other. He told me the next day, as though the hedgehog-pushing incident had formed a bond between us, that he enjoyed painting nude portraits of his wife, and, despite myself (because she was also an elderly German) I found myself imagining her sitting there like a giant chess piece as he splattered paint on a canvas.

Back in 2010, the mystery noise continued and I was still awake. And there was something else: a muttering, a one-sided conversation, a bedtime story being told way past anybody's bedtime. I got up and went downstairs and looked out of the window; the streetlights lit up nothing that could possibly make a noise. I unlocked and opened the door and looked out into the cold, pre-dawn air. Far away on the bypass a car sped towards Grimethorpe. A very early bird cheeped feebly. And that was it.South Yorkshire was just about as silent as South Yorkshire ever gets in the 21st century.

I went back into the house. I stood in the kitchen and the fridge made the sound of a fridge. I went back to bed and there was the noise again; the talking, the scraping. Was there somebody on the roof? Was Mr Lowe still up next door, watching Countdown repeats on the telly?

I heard muffled laughter. Laughter? Who was laughing at this time of night? Laughing's a daytime thing, surely? My wife woke up and said: "That's Andrew swivelling on his chair." She went back to sleep. Of course: my son, home from university, in his bedroom in the loft, talking to his mates on the phone and turning and turning on his chair just above my head.

I knew that, of course. I wasn't scared. I knew it wasn't a giant

hedgehog or a naked octogenarian German lady. Goodnight!