The respectable titles to give would be 'Middlemarch' or 'Howards End'. Both pulled me up short in my late teens with their ability to make me care deeply about the emotional lives of unimportant people. Until then I'd thought novels were purely for bravura storytelling. I hadn't noticed that, at their best, they involve a curious chain reaction of empathy linking reader, writer and character which leaves the reader not simply moved, but somehow altered. But I fear having to dissect and write essays about Eliot and Forster made them less an influence on me than they might have been.
The honest answer is probably 'The Bell' by Iris Murdoch. I was horrified by meeting Dame Iris at a student dining society and having to admit (to her kind relief) that I had read nothing she'd written. I read this first, at her suggestion, then was hooked to the extent of reading no other author for pleasure for the next two years. That had the effect of blurring many of her plots but this one continues to stand out, perhaps because it is so simple.
A young, errant wife re-joins her humourless husband in a lay community, set up on the periphery of a closed order of nuns by an ill-assorted group of enthusiasts. As if re-enacting the subversion of a young nun said to have once brought a curse upon the abbey by taking a lover, Dora acts as a catalyst on the others. Cracks open in the community's ideals before she leaves her husband for good.
Like the best of Murdoch's novels, 'The Bell' is about love and freedom, the interplay between the two and the destructive force of love-gone-wrong. As for many gay men, it startled me in the way it quite calmly adds homosexual love to the general mix. There's no fanfare or politics; it's not the being gay that interests her, simply the effects of loving someone you're not necessarily allowed to possess. As in most Murdoch novels, there's an air of playful artificiality. On one level she knows a novel doesn't matter – she writes for intelligent readers who should probably be doing better things with their time, like healing people or teaching Greek philosophy – and her dialogues exist on a bright, self-aware plane that's not quite real, as though the characters were on stage.
But on another level she's writing about the only things that matter – love, goodness and how to be happy without hurting others – and, like her hero Plato, is using a seductively "easy" medium to bring us to deeper understanding. As in many of her later novels, there's an element of the magical. Things happen which lie beyond the ken of the intellect. But Murdoch has no sooner granted us this little glimpse of the transcendent than she remembers she has a novel to write, and lets the clockwork of her comic plot sweep the characters about their business.
"There again," she seems to say, "Perhaps it is all a game..." Just typing this make me itch to find my battered old copy right now.
Patrick Gale's novel 'A Perfectly Good Man' is published by Fourth Estate