‘I’ve got something to tell you,’ confides Jim Cartwright, in a rascally, Lancashire drawl. ‘I used to be called Maureen.’ But, as it turns out, that wasn’t where he drew the inspiration for his novel, Supermarket Supermodel. A chat with the Northern playwright, whose script for The Rise and Fall of Little Voice was turned into a film starring Jane Horrocks and Michael Caine, is a warm and pally thing, with never more than a few minutes gap between a pun or slowly-released chuckle.

In truth, Cartwright’s lightbulb moment took place in a Tesco queue. ‘I saw this checkout girl; she was absolutely beautiful, and completely natural. I guess I liked that she didn’t have any clue how beautiful she was.’ Walking away with his shopping, Cartwright imagined where she’d end up if she was plucked from the humdrum of barcodes and Club Card points and swept towards stardom. And so Linda was born, scouted during a shift at Safeshop and, ‘taken on a wild ride that goes all over the place, from high society to the lowest of the low.’

This Cinderella story of a working class lass turned jet-set cover girl soon descends into something far less glossy. Linda’s pressured and surreal new world drives her to hard-drinking until she loses the plot completely, crashing face first like a catwalk model in designer heels. Among the obligatory chocolate-haters and casting couch pervs of the modelling world, Cartwright has added a few colourful cameos, creating a showcase for the people-watching skills and camp wit that have landed his plays a place on university and A-level curriculums.

There’s Jackie Collins, who Cartwright describes as, ‘the epitome of a feminine, but powerful woman who never takes herself too seriously’. She floats in, fairy godmother style, when Linda runs to LA to escape her controlling manager, a well-groomed ex-Glasgow hardman. ‘If he was based on anyone special, I’m not letting on, love,’ mutters Cartwright, mock hush-hush. ‘He’d be after me with a Glasgow kiss.’ Or Suze, a whippet-thin Pilates instructor who’s working on a self-help manual. ‘I know a lot of these life coaches are absolute nutters,’ adds Cartwright. ‘But I do love that idea of allowing yourself to be extraordinary.’

While his Lancashire upbringing won’t allow him anything as poncy as bragging, his CV reveals a working class boy whose award-winning plays have ended up being toured internationally. ‘I suppose there are some similarities between Little Voice and this book, with the small-town hustlers, and people chasing dreams. But for me, a novel was an exciting departure.’

Before it’s published, he’s busy directing one of his plays, writing a specially commissioned play about Lowry for Manchester’s theatre of the same name, and still squeezing in time to daydream. He quite fancies acting in a film one day, or trying his hand at stand-up. ‘With a novel, you can set it on the moon with 20,000 people, or spend eight pages describing a toothbrush. There’s no actors or producers or set designers to think of; it’s just you and the reader letting your imaginations run wild and entering a world together.’

Supermarket Supermodel is published by Doubleday on Mon 14 Jul.