Return of the native - Kate Muir interview

"SO KATE MUIR, JUST HOW decadent are you?" An odd question to ask a politely attentive mother of three just before she heads off to pick up her eight-year-old daughter from karate class. Odder still to be asking it not in the private dining room of a Michelin-starred restaurant where coked-up art dealers and millionaire Russian buyers are eating sushi off the naked body of a beautiful model but in the altogether more respectable surroundings of the British Library's cavernously echoing caf.

But a fair question too, considering the amount of white powder that goes up the nose of Fergus MacFarlane, the BritArt photographer who is the main character of Muir's third novel, West Coast. It opens with him eating shrimp from the belly and scallop from the breast of just such a naked human sushi plate while his Harrovian art dealer partner makes yet another lucrative sale of his work. Fergus then jogs back to his luxuriously minimalist Belsize Park home, because that's the thing we're meant to understand about him right from the start: that he's not just decadent, but driven, that he's got to make each minute count.

I don't get much in the way of an answer from Kate Muir about decadence, but nor do I really expect to. No, she hasn't ever eaten sushi off a naked model, but she does know where there are places – New York, not London, admittedly – where you can do so. It's journalism that has taken her to interview people with the whiff of decadence about them – transvestites, rent boys, the London celebrity art world – and it's not her natural milieu at all.

Of course. But talk to her about the other key trait in Fergus's character – his compulsion to achieve – and it's a lot easier to see where he got that from. Muir, a successful journalist (columnist on the Times, former correspondent in Paris, New York and Washington) and novelist (her last, Left Bank, sold 100,000 copies) admits that she shares her protagonist's work ethic.

Like him, she has come down from Scotland to be pretty much near the top of her profession. If Fergus had to leave behind his small-town childhood in the fictional fishing port of Burnoch before he could become a poster-boy for BritArt, Muir has made a similar transition from a working-class background in Clydebank to at least the middle-range peaks of the London media establishment.

"I do share Fergus's attitude to work," she admits. "I feel edgy if I'm not working, and my husband (Times writer at large Ben Macintyre] is the same, so often even on holidays one of us is typing away in a corner doing a book. It's not even a money thing, just the pleasure of making a book as good as it can be. So while this is the first time I have really written about modern Scotland, this book is also about the contrast between the decadence down here and the Presbyterian work ethic up there.

She's noticed that phenomenon many times among high-achieving Scots in London. "About five years ago, I went to interview Gordon Ramsay in his house. He was very proud of it, and as he showed me round his library he was saying, Scot to Scot, that we were both down in London and had done very well. Now he really has got that work ethic. He's the most driven man I've ever met. He told me that when he finished work, where he'd been something like from 9am to midnight, he ran home from Claridge's to Wandsworth: at two o'clock in the morning, he was still going. That image stuck with me. I wondered: 'What would the history of a man that driven be like?"

Fergus MacFarlane hardly has an easy start in life: his father, a fisherman, drowns at sea when his son is only eight. The funeral was the first scene Muir wrote, but already she could see what followed on from it. In London, she'd met a lot of high-achieving Scottish lawyers and financiers who had lost their fathers early in life. Like Bill Clinton, who once said, "I had to lead two lives – one for my dead father and one for myself," Fergus's early loss would fuel his ambition.

Unlike Clinton, though, when it came to drugs, Fergus definitely would inhale. He'd do more: harder drugs would become a routine part of life. For Fergus is damaged, dangerous; chippy about his west of Scotland roots at the same time as he's ready to exploit them, realising full well that his difference from the bourgeois boho herd is a key part of his cachet.

Although Muir has fun excavating the 1970s Scotland of Fergus's boyhood, that long-dead land that had never heard of prosciutto, kiwi fruit, pt and olives, where the diet didn't range much beyond fish suppers and Lorne sausages, Fergus himself seldom emerges as a likeable character.

He's not meant to, she says. "He was much harder and tougher and more vicious in the original and my editor told me people couldn't empathise with him. But I did."

As Nabokov once said, though, understanding the writer's aims is far more important than whether or not we like the character. And Muir's purpose is twofold: not just to delineate the narrow-minded, socially restrictive small-town Scotland Fergus came from but to chart a way out of it, even if the success he soon wins turns out to be appallingly empty.

Any parallels between Muir's own life and Fergus's are intermittent at best. She doesn't even, I point out, sound the slightest bit Scottish: her accent is a completely classless, unregional English. At which point, she starts speaking in a Glaswegian so broad it's almost breathtaking.

"I did have a Scottish accent, growing up," she says. "I grew up in Dalmuir, near Clydebank, at a time when all the local industries were in decline, but I went to this posh school (Westbourne] which is now mercifully closed down. But after that I went to read law and politics at Glasgow University, where the more you spoke with a working-class Glasgow accent, the more street cred you got.

"After that I went to Cardiff to do the post-graduate journalism course and was intending to go on a radio course. They did a little analysis of everyone's voices, and for me they just wrote: 'Scottish accent'. Certainly when I went to work on my first newspaper job in Ealing, I had developed this very strong Glasgow accent and talked very fast and swore a lot and no-one could understand what I was saying. But because in this business you have to make yourself very clear to people, I became this non-accent person."

When she was writing about Fergus, she says, one of the passages that flowed the easiest was when he first caught the bus south. "Because that's a great moment in many Scots' lives. When you take the Citilink bus from Glasgow at night, through the orange sodium lights leaving the city behind. The still caf on the motorway at four o'clock in the morning, and the realisation that your life is about to change. For Scots, that's like the boat taking you to the New World: it's a very powerful image for me. I took that bus a lot when I was at university."

She's been lucky in journalism, she says. "I was working at a time when papers still had foreign correspondents and gave them the time to drive through Mississippi or wherever and spend five days on a story. You just don't get that now." One of those American assignments – a Texas prison factory where death row inmates make uniforms – resurfaces in the book as the basis of one of Fergus's exhibitions.

For all the success of Fergus's photography, however, the vacuity of the London art world becomes ever more obvious. Whatever he's searching for, he won't find it in his well-paying portraits of the latest music sensations, drugs or casual success. It's as if, amid the trappings of unsatisfying celebrity, the lyrics of Dougie Maclean's Caledonia are sounding out ever louder in his head. Only in Scotland, the country he had to get away from, can he find some sort of redemption.

I don't see Kate Muir following his example, upping sticks and settling back in Scotland any time soon – even though she points out that she goes back to the family home in West Loch Tarbert as often as she can. The fact that she and her husband both took evening classes in boat navigation last winter is a statement of intent about future holidays sailing off the west coast.

Scotland – throughout the book a necessary correction to metropolitan excess – clearly matters to her.

"The thing about roots is that they keep you upright," she says. "They're the ballast in your life, the thing you're never going to throw away."

West Coast by Kate Muir is published by Headline, priced 16.99. Muir will be appearing at the Borders Book Festival in Melrose on Sunday 22 June at 6pm.

Kate Muir on …

Writing novels in the British Library: "I work in the rare books room, invaluable when you want to check up on things like guides to Scottish seaside towns in the 1970s. I'd be there for five hours at a time and you'd come across the kind of detail you'd forgotten about – like krypton tuning for cars – and just go inwardly – yesss! There's a whole coterie of scribblers, and often we'll text each other and meet up for tea in the caf. I love it."

Interviewing celebrities: "I started off at the Times doing all these Hollywood people. I remember interviewing Arnold Schwarzenegger: he asked me about my bra size and I got very annoyed with him and wrote up the interview verbatim without tidying it up. Of course, I got banned by that film company, but when you're young, who cares?"

Editing: "I love the writing, but editing yourself against a deadline is hard. I had to take out 100 pages about Fergus and put another 100 back in, working late and getting up at 5am because the book was already in the catalogues."