Picture a room, a huge room the size of an aircraft hanger.

The room is brilliantly lit which means that everything in it can be picked out in the minutest detail.

The room is in an otherwise anonymous industrial estate somewhere at the edge of town and it’s guarded by security personnel with dogs and torches brighter than Oakwell’s floodlights.

Maybe the room is one of many. Maybe the whole industrial estate is full of rooms just like this one, exact replicas of each other.

Or maybe, and this could be more chilling, this is the only room of its kind in the country.

Or even the world. Let’s take a look inside the room: it’s okay, I’ve had a word with the guards and they’ve let me in, turning multiple keys in multiple locks and turning the alarms off and getting the dogs to sit.

Inside the vast cavernous space there are rows and rows of boxes stretching as far as the eye can see.

The boxes are stacked on top of each other and they more or less reach the ceiling.

It is so long that I bet it’s a different time zone at the other end – it makes that Evri warehouse at Hoyland look like a doll’s house.

Each of the boxes is numbered and here’s a sign at the end of each row that tells you which row you’re looking at.

I know, this feels unreal. It feels like a science fiction film or a computer game. You might expect Dr Who to pop up at any moment, or Captain Kirk to get beamed down and then beamed up again. It’s the opposite of unreal, though. It’s real.

I’ll tell you what happened. I sat on a bus in the early evening the other day and the bus was warm even though it was cold outside.

Because the bus was warm and the ride was rhythmic and I’d been up early like I always am, I started to feel drowsy.

I decided that taking my hat off would make me feel a little cooler and maybe not quite as sleepy and it did, briefly, but then I started to nod away again and my Zs began to fill the bus (and I wasn’t the only one, lots of us were snoozing) and then suddenly without any warning it was my stop and I got up in a hurry and dashed off the bus into the cold so I reached for my hat and of course I’d left it on the seat and the bus had trundled away and I was hatless.

I felt bereft. I felt hat-bereft, which is like being bereft, but worse: your ears get cold. I remembered exactly where the hat was from: it was from a shop in Cleethorpes, bought one day when the wind was straight from Siberia. It was a good hat too; not too tight, not too floppy. Kept my head warm but didn’t make me sweat. A perfect headpiece.

I walked home from the bus stop through the fridge-like air. Ah well, I thought: another hat lost, to join all the hats and scarves and bags and all kinds of other human detritus that I’ve lost on public transport over the decades. Ah, but lost where?

Well here it turns out, in this vast warehouse-like space in this anonymous industrial/post-industrial area. I’d heard rumours of these places where all the things you lose end up – a kind of mammoth lost property office, a treasure chest of misplaced treasure.

I did a bit of research online and found out, to my surprise, that everybody has one of these storage spaces where all their lost things are saved. For those efficient and careful types who lose very few things the space could be as tight as a small garden shed but for champion losers like me they can be in endless Palaces of Forgetfulness like the one I was standing in.

I opened one of the boxes and saw the toy car I left on the 37 bus in 1966. In another box there was that McMillan Tartan scarf I lost (appropriately) on a ferry to the Isle of Mull in 1981.

There was that copy of the Beano I left on the LP bus in 1964 and the poetry magazine that slipped between the seats of the train to Barnsley just after it left Wombwell station sometime at the start of this century.

And the hat I lost the other day? I’ll keep looking…