A statue, maybe. A bigger-than-lifesize bronze in the middle of Darfield with my bronze briefcase held aloft and my bronze thumb raised.

Perhaps a blue plaque at 34 North Street: "Ian McMillan Was Born Here in 1956", and another one at the site of the old Low Valley Infants School, now the new Low Valley School: "Ian McMillan studied here, 1960-1967, And This Is The Spot Where He Watched Mrs York Chase a Goat Out of The School Hall Using a Window Pole in 1963."

Maybe that's a bit much for a blue plaque. I could have a big gravestone with a poem on it, one that I'd composed specially and left in a buff envelope to be opened after my death: "Here Lies Ian McMillan/some thought he was a villain/but he always did his best/in Summer discarded his vest/and you could say one thing about him: at least he was willin.'' I like the idea of being remembered by a terrible poem.

I was thinking about this the other day, wondering whether I should be stuffed or just have a cul-de-sac named after me, as you do when you get past 50.

I was sitting on a train going to Goole and I leaned towards the window to get a good look out because it appeared to be misty and I like looking at the sun peeping through mist.

However, the mist seemed to be a bit odd, a bit otherworldly. I touched it. It was hair gel, smearing the window and giving the countryside round Stainforth an impressionistic quality. I withdrew my hand quickly but then I thought: well, whoever it was who had leaned on the window, possibly asleep, possibly with their mouth hanging open and a skein of dribble snaking towards their lapel like the start of a spider's web, had left their mark on the world.

This window-gel was a bit like a statue or a blue plaque. It said: "I was Here, I left This", and after all, isn't that just what a statue does?

This got me thinking about the other tiny memorials of ourselves that we leave everywhere, often accidentally. I'm not talking about graffiti or those signs that you sometimes see hanging from motorway bridges saying "DOREEN IS 50 TODAY" because they're too deliberate.

They need to be unplanned to have the certain poignancy that the gel-on-the-window had; had the person who'd been sitting there had a late night and had they nodded off and missed their stop? Had they been leaning against the window because they felt too overwhelmed by their life to lift their head and look at the fields?

You get into a lift and there's a whiff of perfume or bacon sandwich or worse. You're the only person in the lift but somebody has left their spoor. It's like finding a tiny fossil on the beach; it's evidence of what was here before, something somebody left behind, and not necessarily for you to find. That's what makes this kind of thing so intriguing, for me.

You're crossing a bridge and you don't move quickly enough and you end up on the photograph the man was taking of his wife. Well, not much of you ends up on the photograph because you were walking fairly quickly. There's just a hint of your trailing leg, there, at the edge of the snap. You're immortal, or your leg is. People are looking at the picture years later and they're saying, "What's that smudge?" and the person who took the picture is saying, "Oh, it's just some fat bloke who got in the way."

I look at the back of my neck when the barber shows me my haircut in his mirror, and it's the back of my dad's neck, and again, that's a kind of immortality.

When my grandson Thomas grows up, the back of his neck might look like the back of my neck, which in turn looks like the back of my dad's neck. Before you know it you're hundreds of years away at the roots of a family tree and the back of that bloke's neck, the one in the field eating the turnip years before the Industrial Revolution, looks like the back of Thomas's neck.

We leave evidence of ourselves everywhere. You make sandwiches for somebody and they take them to work and there's one of your hairs in the lettuce. You whistle a song, maybe a minor hit by The Peddlers, and for days the person who passed you in the street just as you were getting to the chorus, can't get the song out of his head. He whistles it later that day, and somebody else can't get it out of their head.

Statues are irrelevant, really, aren't they? All we need is a bacon sandwich in a lift and nice tune to whistle in a crowded place and people will remember us.