My head felt hollow, like a big old empty steel can. It reverberated mightily with the slightest provocation – when I closed my teeth together the resulting sound made my whole head ring. This felt like some bizarre new trick that I had never come across before so I experimented with it for a while, the way you would when you discovered something new to do. Then I stopped – it just felt too weird, it was weirding me out.

As I walked my trainers didn’t quite seem to make proper contact with the pavement. It was as if they couldn’t quite reach – they almost touched the ground but not quite. Frustratingly, I couldn’t seem to make contact with anything solid. Everything felt spongy. My damn trainers felt like two over-large wet bathroom sponges – all squishy and soft and flabby. Old grey bath water oozing out of them everywhere I went. No bounce in them at all. No bounce in anything, just rotten sponginess. A dead kind of sponginess. What the hell was wrong with me, I wondered. Was I sick?

This thought too – unspoken though it was – reverberated loudly back and forth in my apparently empty skull with quite unreasonable violence. It repeated, gaining in volume as it did so. I had the impression that there was a lot of space in my head, only it wasn’t the good kind but the stale, stodgy, stagnant kind. It was dead space. My head was full of dead space. It felt dreadful. Why did my head feel so big? Why was it so echoey and vast? These thoughts too repeated.

I swallowed nervously and the noise was instantly amplified, becoming all spooky and strange. When I cleared my throat the echo practically deafened me.

I was walking down Hounslow High Street, on my way to the café by the bus station to get myself a cup of tea and a plate of egg and chips. I figured that food might make me feel a bit more normal. Which was rather optimistic, I realized, given the way I was feeling. I was feeling spectacularly awful. Really awful.

It amazed me that I felt so bad. What had I done to deserve this, I asked myself? It didn’t seem fair. The thought echoed unpleasantly in my head and I winced involuntarily, wishing I hadn’t bothered thinking it. I stood still, waiting for the mocking echoes of my own self-pitying thoughts to die down, and then continued on my way. Hounslow High Street was busy as usual. Pointless frenetic activity, it seemed to me. What was it all for? Why where people always running around the way they do?

What was it all for? What was it all for? What was it all for? repeated spongily in my head. An insanely squawking choir of my own jeering thoughts. Chirping like crickets – taking the piss out of me. I wanted to curse, but refrained. Had to try to shut off all the thinking before it drove me mad. Every new thought just added to the mocking chorus. I had to learn to say nothing. Bite my tongue. Make no comment.

My head felt so very big. Big but empty. Lots of things were happening in it, but only stupid things. No good things. None of it made any sense.

People were in my head. Buses and taxis were in my head too. Pedestrians. Exhaust fumes and jet planes. Everything was in my head and at the same time my head didn’t feel capable of containing anything properly. My head was rotten, decrepit, defunct. Like a big old rotten pumpkin, it was in danger of collapsing in on itself. Caving in under its own weight.

I wondered how I had the strength to carry such a huge head around with me. How could I support it? My head was as big as the world at this stage – it had the whole world in it. My head was the world or the world was my head. I wasn’t sure which.

I was walking around in my own head. Only it wasn’t my head, not really. Not any more. It was something else. Or maybe it was my head all the same – but also not my head. I was confused on this point. I gave up trying to work it out. It didn’t make any sense.

Things settled down after I stopped trying to make sense of what was going on. After a while it became clearer to me – the reason I could walk around with such a big head was because it had become very light. There was air in it now, a feeling of breezy spaciousness. Air was coming in and going out and the rotten stodgy stagnancy had been blown all away.

My head was like a huge airy tent. Or a helium balloon. My head was a balloon and it was ballooning. Expanding ever bigger, encompassing more and more. Getting lighter all the time. Bigger and lighter, bigger and lighter, bigger and lighter.

It occurred to me that the bigger it was the lighter it got, which came as a great relief to me. It was very light indeed. Too light, in fact.

The membrane around it was getting very fine now, I realized. A monomolecular layer which couldn’t stretch any more. Like the edge of a soap bubble. And the soap bubble was sooner or later going to burst. Had to burst…

The two-dimensional surface of the balloon was rushing outwards through space at a tremendous speed now. An awesome speed. Like a horse galloping through a field, tail and mane being whipped by the wind. Like a hurricane sweeping along. Like a mighty wind, racing ever faster across the land.

I knew it was approaching the mathematically defined point at which the fast-moving membrane was to give way. I knew this beyond any doubt. Give way to what, I did not know. I could not imagine. Some strange magical realm perhaps, a realm beyond my imagining.

All I knew was that the bubble was about to burst…