Landscapes of love: How Patrick Gale's insight into women and men bore rich fruit

The fresh-faced, debonair 46-year-old sitting before me in the lounge of a London hotel is, undoubtedly, big news. Nobody could be more surprised than Patrick Gale himself, HarperCollins's biggest selling novelist last year, and author this year of two volumes of fiction. Gale is in the midst of a promotion tour for what is, remarkably, his 14th novel, The Whole Day Through (Fourth Estate, £15.99 & £7.99). In October, he will set out again to bat for a second collection of short stories, Gentleman's Relish.

Gale's career had been in the ascendant this past decade, as he steadily built on a solid, early, gay-ish fan base, adding that essential demographic which makes up two-thirds of all novel sales: the woman reader. Still, his last novel remains the game-changer. Notes from an Exhibition (2007) is a darkly psychological account of a woman artist based in Cornwall, and the havoc wreaked on her family by her single-minded careerism and, more palpably, her extreme bipolarism. Selected at the eleventh hour for the last Richard and Judy Book Club season aired on a terrestrial channel, the novel leapt into the paperback charts, ensuring interest also in a diverse back catalogue.

Asked to reflect on his output, Gale laughs uncontrollably. "Well, I'm really embarrassed by my early books now. I recently had to reread them all. They're being re-issued, and I decided to write an essay for each one... It was enormous fun. I found myself going back into photograph albums, just to remind myself where I was at the time.

"But they felt so young. I was so young – 22, for the first two! I knew nothing." Readers of Gale argue over which novel has the edge. I alternate between 2000's Rough Music, perhaps the most "Cornish" of several titles set in the county he inhabits and loves, and the last-but-two, a relatively overlooked school-bound saga of love and betrayal, Friendly Fire (2005). That novel was set in Winchester, the city in which Gale grew up and to which The Whole Day Through returns.

The author feels haunted by a much older title, 1986's The Aerodynamics of Pork. "Of the early novels, that's the one which, strangely, continues to sell. It seems to have a place in the gay canon over which I've no control. And it's totally out of date in so many ways. It was written in the shadow of Clause 28 when we had virtually no rights. It's such an angry book. It feels historical today."

Some fans have expressed disappointment that Gale's stock of gay characters has felt somewhat depleted in recent years – in the novels at least. (In Gentleman's Relish, there's an extraordinary racy and romantic gothic story, "Hushed Casket", featuring a domesticated gay couple whose sex life is bizarrely transformed). But Gale simply draws on his broad human understanding – in, for instance, writing so well about women's hopes, needs and disappointments. It's hard to think of a contemporary male writer whose take on women has been as celebrated – though when I mention this, Gale characteristically offers his candidate.

"What about Colm Tóibín's Brooklyn? It's the most depressing read for a novelist. You just think, 'Oh shit, I might as well give up now.' If anyone thinks you can't convey passion with non-passionate language, they need to read that novel. It conveys such a powerful sense of this woman's psychology and her tempestuous feelings, while using such quiet language and a modest vocabulary. And if I've learnt anything in the past 20 years, it's that you need to leave stuff out of a novel."

Tóibín is among a small group of gay authors – including Alan Hollinghurst, Philip Hensher and Sarah Waters – whose novels have transcended the perceived market limitations of "genre fiction". It's a key virtue for publishers in lean times. About Richard and Judy, Gale is equally modest. "Boy, was I lucky! But I only got in as an honorary girl. It was an almost entirely male shortlist. Then it was between mine and another book, which also dealt with mental illness. I'm convinced the reason they picked mine is that... most of my readers are women. They thought: 'Gay man read by women – he'll do'."

Still, the success of Notes from an Exhibition did not come without tensions. "It was set to go into the most hideous paperback edition. The publisher showed me this cover image that had nothing to do with the novel. I was very upset. It showed a girl in the wrong clothes on a beach that clearly wasn't anywhere in Cornwall." Then Amanda Ross – the Cactus TV boss who selects for Richard and Judy – said: "'We won't touch it with that cover.' So HarperCollins frantically went back to the original photo shoot and came up with a brilliant cover, using a rejected image of these women's hands. Inevitably, HarperCollins are a very commercial company. They're not going to do an arty cover when the one they've given it will sell more. But I'm a bit disappointed that The Whole Day Through looks so girly. I was at pains to make the novel a 50/50 split, in terms of including the outlook of both the man and the woman in this relationship."

The novel's appearance does, as Gale goes on to claim, somewhat resemble airport fiction – a genre it couldn't be less like inside. It's a taut, sometimes melancholy, deftly-plotted fiction concerning an adulterous relationship. Ben and Laura first met as students, and are reunited after two decades. There's Gale's capacity for making the apparently improbable motive or behaviour seem inevitable and "true". His ethical concern – the Iris Murdoch side, if you will – is just as conspicuous. And the novel comes with a disarming twist – about which we'd better say nothing.

One critical plot development relates to how Ben, a married man who falls (again) for the single Laura, chooses to keep in contact. He hesitates between using his mobile phone or email account, writing a letter or paying a visit. Our proliferating contemporary means of being in touch are neatly contrasted with the undergraduate practice of leaving a sheet for messages on your college door, which Gale fondly recalls.

"I kept the 'sign-up sheets' from my last Oxford term because they're so poignant... My initial thought was to write a sort of latter-day remake of Jane Austen's Persuasion. I was interested in writing about somebody being too influenced by their friends.

"I was tremendously in awe of mine at Oxford. I don't think they realised how much power they had. In one notable case, they got me to dump a boyfriend they didn't like. One sheet I kept has several messages left by a friend urging that... I started wondering, 'What gave them that power over me?'"

He based himself in London after graduating in 1983, starting out in a bedsit in Notting Hill. Though his website proudly reports that he "has never had a grown-up job", Gale supported himself while writing his first novels – The Aerodynamics of Pork, Ease (also 1986) and Kansas in August (1987) - by typing, ghost-writing, book-reviewing and, most winningly, working as a singing waiter. He moved to Cornwall in 1987, to Camelford, where he wrote his "mid-period" novels: Facing the Tank (1988), Little Bits of Baby (1989) and an all-woman novel, The Cat Sanctuary (1990). An epic family saga, The Facts of Life (1995), won Gale the attention of Armistead Maupin (whose biography he has also written). Rough Music saw Gale published to critical acclaim in the US, where one reviewer pre-empted R&J, arguing: "If Oprah takes British writers, this is a shoo-in".

By the time I revisit Rachel Kelly's mental illness in Notes from an Exhibition, I'm again dizzied by the extent of Gale's interests, and dazzled by his sheer prolificness. As for its sequel, The Whole Day Through "shifted towards Brief Encounter. Oh, and Penelope Mortimer's The Pumpkin Eater, a wonderful novel. I had some arguments with women writers I know, who said that you couldn't do a Brief Encounter-style love story any more, because women are so conditioned now to have what they want. Happiness is almost a moral right. Daring to suppress your needs, to compromise in order to be good, is perceived as unhealthy. Your therapist wouldn't approve. But I begged to differ. There are people out there who would still do the decent thing.

"It's also a book about memory, which I'm obsessed with. Memory runs to the heart of narrative; to our personal narratives. We comfort ourselves by gently re-editing our own story."

I mention that Gale has praised other writers for their "therapeutic insight" into how people play such games. "Well, psychotherapy's my lost career. If we had a revolution, and all bourgeois novelists had to retrain as something useful, I'd sign up to become a therapist."

Meanwhile, he helps out on the farm near Lands End run by his long-term partner, Aidan. "I'm just the extra pair of hands. But it balances things out nicely. I've always been a keen gardener. Farming's just gardening on a bigger scale. It gives you release; you're physically tired after farming, whereas, as a novelist, your brain gets exhausted but your body's still wired. So a lot of writers can't sleep while working on a book. And that's why so many become alcoholics – to knock themselves out at night. I never have that problem, with the combination of sea air and being out of doors."

For the near future, farm life must go on without Gale, as he sacrifices rural seclusion to spread the word on The Whole Day Through. It's as good a place to begin investigating his many talents – in the unlikely event that you haven't already started, that is.