18/02/2014 17:11 GMT | Updated 20/04/2014 06:59 BST

Eight Minutes Idle From Book to Screen

I've always found offices at night fascinating places. Whenever I walk around streets at three a.m. and look up and see a solitary worker still at his or her desk I can't help wondering what they're doing and remember the time when it was me alone on the third floor of an office block in the middle of the night.

I used to work in a call-centre. I started with the day shift, then after a while I switched to nights, though for a brief while I did both and considered sleeping in the cloakroom in between. I could never quite bring myself to do it- the carpet tiles looked too uncomfortable. But I decided to write a novel about a man named Dan who did.

8 Minutes Idle sold well and won a literary prize and was recently made into a film with the very charismatic Tom Hughes. I co-wrote the screenplay and because all the call-centres I'd worked in had been pulled down, the set designers built a new one. The director and I wanted the office to look like a strange but welcoming environment, so that Dan's decision to sleep in the stationary cupboard after his mum kicks him out seems almost normal.

I'm from Bristol and the film is set there and at the first read-through the actors were trying out their wildest West Country accents- sounding like the Wurzels after seven pints of scrumpy. One of the producers told the director he'd like it if the actors had softer Bristolian accents more like his. "But," he protested, "I'm from Lincoln."

The accents soon settled down and everyone seemed convincingly West Country or near enough. The best part of the experience was watching the actors add a new dimension to characters I'd lived with for years. Ophelia Lovibond brings just the right note of mystery to Dan's secretive workmate Teri. Antonia Thomas nails the sexy hauteur of part-time DJ Adrienne. Monserrat Lombard is truly convincing as the world's most terrifyingly unpredictable boss and Paul Kaye and Pippa Heywood are the kind of parents that might prompt even the sanest man to swap his home for the office.

Dan's parents play quite a large role in the story. My mother is not a psychopath like Dan's and my father's (a little) more responsible than his fictional counterpart. They're divorced now, but my mum did say if she was married to Paul Kaye instead of dad, she never would have left him.

When Dan heads to the office, he takes his cat with him. It's a strange coincidence that our John the Cat hits cinemas just a few weeks after the Coen Brothers Inside Llewyn Davis features another man struggling to take care of a ginger tom (look, I did it first, do we have that straight, Coens?). Without giving anything away, I think our cat has a far more dramatic time of it. He even has his own Twitter account. It's strange to think because years ago I decided Dan should smuggle his cat into the office, one of the marketing team is now sitting at her desk wearing cat ears and whiskers and channelling her inner thespian feline.

In the process from script to screen sacrifices have to be made. One of the scenes we were all delighted with was a ménage a trois where a woman ends up in bed with one man dressed as the Bristol Rovers pirate and the other as Bristol City's confusingly-named mascot Scrumpy the Robin. Unfortunately neither football club would give us permission to desecrate their poor mascots in this way. The threesome's still there, but it's a very different scene now.

When you're writing a novel you don't have to listen to anyone. Your agent or editor might have opinions, but it's easy to ignore them. With a film, you have to listen to everyone. If you fight too hard early on people stop consulting you, and you soon discover nothing's written in stone till the cameras start running, and there's still a million more decisions to be made in the editing room. And even once the film's locked there's still loads to be agreed upon, from the poster to the trailer to the location for the premiere.

8 Minutes Idle was released on Valentine's Day. It is a dark romantic comedy, but with an emphasis on the comedy as much as the romance. In the novel, poor Dan doesn't even end up with the woman he most desires. I'm not going to give away the movie's ending, but the moment the director came up with it (and I have to give him full credit for this one), I realised it was the perfect conclusion. Any more than that, I'm not at liberty to reveal.

Matt Thorne will host a free film talk sponsored by Jameson at The Alibi, Dalston, on Thursday 7-9pm. To RSVP contact