I found a wallet in the street with two identities in it. Which is the real one? Why carry both at the same time? Surely that’s a schoolboy error for any spy.

I rifled through the wallet to see if there was an easy way to return it to its owner, then set off to the police station to hand it in. It was one of those days where sights and sounds were slightly heightened. Rain hissed onto the tarmac and tapped the hood of my waterproof. A man was walking in ridiculously clippetty-clop shoes, as if he’d had them repaired by a 19th-century blacksmith. Maybe this is a new fashion, having your clothes and shoes fixed using bygone technology.

I passed a girl whistling loudly up to an apartment window – another throwback to an earlier time, before mobile phones. I remembered doing that as a student. I would stand in the street and shout my friend’s name, and he would shamble down in his flip-flops and usher me into the communal kitchen that was always high with Chinese cooking. Now I heard a security keycode door click open, the same solenoid sound the world over. The sound of mistrust, of sparse staircases that smell of damp socks and open onto lifeless streets.

The term ‘subtopia’ was coined in the 1950s by the architectural critic Ian Nairn to describe how suburbs spread into the countryside, offering residents the dream of escaping the city but resulting in a characterless averaging-out of places. In America they call it ‘Anywheresville’, the lowest common denominator town. But Subtopia is moving into the city. We accept non-descript buildings. We no longer recognise good new buildings when we see them and we don’t know how to demand them. That must be why we instinctively believe older buildings to be better and mourn their loss. When they go, we know they will be replaced by something that is only average.

In a leafy street I noticed an abandoned house that seemed to have spontaneously fallen down. It had been there as long as I could remember, covered in ivy and fractured by buddleia. Today, suddenly, it had crumpled. What had changed to finish it off and what would happen next? A few more years of dereliction and then maybe some very average new flats. Subtopia’s tendrils are reaching into the genteel old neighbourhoods.

Is this averaging-out, this lowering of expectations, an evolutionary thing? My daughter had recently brought home a book about early people, our distant ancestors on the long journey from ape to you and I. They made stuff with their own hands and their hands evolved so they could do it better. They figured out how to trap and kill woolly mammoths. These were strong people, almost superhuman by our standards. I basked in the self-satisfied glow of my own primal ability to make bread and cheese, or pick fruit from a tree, my middle-class survival skills a feeble nod to these ancient folks who could have broken me like a twig. I couldn’t even figure out which of the two identities in that wallet might be genuine.

I put on my headphones and listened to an interview with a Canadian band who had just recorded an album in a small town that had been hit by storms and floods. The ducks had moved straight in, happily swimming along, escorting their young families on adventures along these exciting new rivers: “Come on kids. Check out these weird caves! Watch out for floating plastic, mind.”

I reached the police station. It was a dead-eyed lump of brushed concrete. At first I couldn’t find the entrance. I had to walk around three sides of the building and still chose the wrong door. Some detective, foiled by nothing more than bad design. I handed in the wallet and walked out into the light. The rain had stopped. At least I knew where I could get an above-average coffee.

Andrew Wood