A group of us had been out for a friend’s birthday and went back to his house in east London to watch the sunrise. There wasn’t much room to sit on the terrace, and the chimney looked like a good spot. I thought it would be dangerous to have my back to the chimney, so I sat on the rim with my legs dangling inside. In hindsight, that was my first mistake.

I was about to climb out when I slipped down. The flue curved, so at first I was able to stop myself. I managed to get my hands free and wave them about a bit over the top of the chimney. Everyone saw them and said, “Look at Leo, he’s so theatrical and amusing.” I’m quite a proud man, and I didn’t want to admit I was stuck in the chimney and spoil the party. But there’s only so long you can maintain a weird hand puppet show. The others got bored and didn’t notice when I slipped again, about seven feet, down to the bottom of the flue, one floor down.

I was worried, but not panicked – I just thought, “I’ve been rather silly here.” I started to shout: “Hello! Help! I’m in the chimney.” That carried on for about two hours. But nobody heard me, and eventually I could hear them all leave the party. That was a depressing moment. Then I tried to get to my phone, which was at my feet, contorting my legs and hands and trying to manoeuvre it up my body, but I kept dropping it.

The chimney was almost exactly as wide as me, and very sooty, so it was hard to get any purchase. That went on for about three hours. Thank goodness my phone still had battery. If it wasn’t for that, I’d probably still be there.

Eventually I got my phone up and called 999. “Ambulance, fire brigade or police?” they asked. “I’m stuck in a chimney,” I replied, and they repeated the question with more urgency. “I don’t know, I’ve never been here before,” I said, then decided on fire brigade.

“I’m stuck in a chimney,” I said when I got through. “You’re what?” “I’m stuck in a chimney.” “Where?” At this point I realised that I didn’t actually know where I was. I called my friend Max to ask for the address. “Why do you want that? Are you going back?” he asked. “I’m still there.” “Really? I haven’t seen you for hours!” “Yes, I’m in the chimney.”

The fire brigade took about 45 minutes to come. The first fireman on the roof declared that nobody could be down there because it was too narrow, and I was shouting “I am, honestly. Come on.” He threw down a rope and dragged me out, which is when most of my injuries occurred – the chimney was quite narrow, and my back scraped along it. I had also taken off my shoes, jeans and jacket as I tried to free myself, so I was only wearing my underwear and a shirt covered in soot. The firemen asked if they could pose for some pictures, because they had never seen anything like it. I obliged. I had been down there nearly seven hours.

I never really despaired, but I did have moments when I thought, “Leo, what are you doing with your life? Is this where you want to be?” I also felt a bit guilty: people don’t pay their taxes so firemen can pull people out of chimneys. But I was relieved to feel the sunlight on my face. Max came to pick me up and cracked the first joke: “Well, you’re lucky you didn’t catch the flue.”

After that, someone posted a picture of Dick Van Dyke on my Facebook wall. Then a shot emerged of my hands sticking out of the chimney, and people Photoshopped them into various pictures: Super Mario plumbing pipes, the poster for the movie 127 Hours, Battersea Power Station. Finally, a video clip emerged of me being escorted out of the building looking like a Victorian urchin.

I’m glad my friends’ response was to make light of the situation. It would have been awkward if they’d been morbid. I’ll never look at a chimney in the same way again.

• As told to Ed Cumming.

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