Irvine Welsh has revealed that he would like to direct a film - as long as it's not based on one of his own books.

The Scottish author, who has already seen several of his novels, including Trainspotting, Ecstasy and Filth, adapted for the big screen, has stepped behind the camera for several short films.

"I wouldn't direct my own books. I would direct a movie from somebody else's book that I liked, or I would direct an original screenplay I wrote myself, but when you've written something as a book, I think you always see it as a book," he said.

"You need a fresh pair of eyes to come in. If it's your own book, you're a bit precious about ripping it up whereas somebody else would tear it to bits to find the film in it basically."

Irvine said that he gladly hands control over to directors such as Danny Boyle (Trainspotting), Rob Heydon (Ecstasy) and Jon S Baird (Filth).

"I say to people when they get the rights, 'Don't be scared about tearing the book apart'. The book will still be there at the end of the day but you've got to be inspired by this material," he said.

"Writers who are precious are just selfish. The film may be different from the book but it's a totally different medium. You have to see it as a story and characters and how they work on screen. Sometimes, in the interests of the audience, you have to leave parts out of it."

Ecstasy is available on DVD and Blu-ray now.