Of course, there was no way I was going to compromise the integrity of my story, which was as follows.

A handsome, dynamic young writer in his early fifties is admired by everyone for his integrity. Except his wife, who throws him out, obsessed by a silly, trivial affair he's been having with her younger sister for the last twelve years. The writer moves in with his best friend, who soon remembers that he has to sell his flat and move to Thailand. The writer flees London and goes in search of his own soul. He enters a nightmarish world of misery, paranoia and self-loathing. But then he decides to leave Brighton and try his hand at stand-up comedy. When that doesn't work, he decides to kill himself, until he meets a beautiful taxidermist. He moves in with her and writes a blisteringly honest screenplay about his experiences. The script sells for millions, and he moves to California with the taxidermist's younger sister.

How could I think of changing that story? Apart from anything else, it was all true, except the bit about writing a best-selling screenplay and moving to California. And I altered some of the details, for example, the taxidermist was actually a taxi driver. No, I wouldn't change it, but I could adapt it.

So, in the new film noir version, the writer is a private eye. His wife doesn't throw him out, she disappears. And she's not his wife, she's his wise-cracking secretary. The character of the best friend is now his partner, who dies in a mysterious gardening accident. The hero follows the trail to Brighton - still a nightmarish world of misery, paranoia and self-loathing - where he discovers that his partner killed the secretary and faked his own suicide. The two men fight on the cliffs and the partner falls to his death. The hero finds comfort in the arms of a beautiful tax inspector, and her sister.

I sent the script to the production company. Three months later I got a very encouraging e-mail saying they'd received my script. I waited another three months, then, by pretending to be Richard Curtis, I managed to schedule a meeting with the receptionist.

"We're not doing noir any more," she said. "We're looking for horror movies."

So, in the next version, the writer is a vampire hunter. The best friend is now his dentist, who is secretly a flesh-eating zombie. When the hero finds out, his wife, an ageless Transylvanian princess who renews her youth by drinking human blood, lures him into the nightmarish world of the undead (Brighton). But he tricks her into drinking the blood of a commissioning editor, which poisons her. He grapples on the cliffs with his dentist, who mutates into a terrifying CGI effect. He's rescued by a beautiful taxonomist who reclassifies the zombie dentist as a harmless fungus.

This time I was able to pitch directly to the senior producer, after tracing his address and hiding in his wheelie-bin. He said he liked the concept but nobody was doing straight horror any more. Now, the magic formula was comedy-horror. He also suggested a few minor changes; he said the hero should be female, the wife should be a mixed race transsexual rap artist (for the youth market) and the best friend should be a dog. Then the bin men took me away.

I changed the characters the way he'd suggested; I made everything ironic, so it didn't have to be funny, and I stole bits from other movies, which is called referencing. I phoned the producer's secretary, who said he was busy for the next two years. But then I bumped into the first producer at an AA meeting. Apparently she'd started drinking heavily after the trauma of being locked in a toilet cubicle with a madman. Me, I'd started drinking heavily so that I could go to AA meetings and meet producers. I pitched her my script. She said comedy horror was very last year. She also said that buried in my script she sensed there was a strong, simple, honest story about a failed writer who confronts the existential void of his own insignificance. The kind of story everyone was interested in now. I went away and rewrote my original script, with updated topical references. When I'd finished, I tried to contact the producer, but she'd left the business and moved to Brighton. So I wrote another script, about how I spent two years not selling my screenplay. It's a bitter-sweet romantic pseudo-documentary horror film noir with a strong streak of suicidal humour. Want to read it? I'm living in my car, but you can find me at all the meetings: AA, NA, or SA - that's Scriptwriters Anonymous, for people addicted to rejection. We bring the problem on ourselves by our fierce, uncompromising refusal to ever, under any circumstances, sell out.

Paul Bassett Davies is a writer and director of Euroscript.