"Stories of all lengths and depths come from different parts of the cave," writes Jane Gardam in the introduction to this fat anthology of three decades' worth of her powerful short fictions. "For a novel, you must lay in mental, physical and spiritual provision as for a siege or for a time of hectic explosions, while a short story is, or can be, a steady, timed flame like the lighting of a blow lamp on a building site full of dry tinder." There is nothing accidental in the incendiary violence of Gardam's metaphor: she may be well into her ninth decade now (and none of these stories was written before middle age), but her imagination crackles with menace. Each one of these narratives – none of them afraid of looking into the great terrifying secrets of love and grief, death, ageing and faith in a mere handful of pages – makes the heart race.
Sly, sharp and mischievous, in these stories Gardam chooses precisely society's quietest and most overlooked characters – the old and shy and sheepish, conservative wives, stay-at-home mothers and impoverished ex-colonials, dwellers in cottages and suburban villas – to explore the fiercest passions. She has an extraordinary ability to enter the interior of the long-lived mind and to illuminate history through it; she is particularly fine on that strain of Englishness trained to repress and conceal emotion, and she entitles the most marginal of figures to love, and to beauty. In "The Boy who Turned into a Bike", silent Clancy with his "inward-turning heart" cycles "up and down the flat windswept roads, in and out of the great curves of the silver River Nene" one frosty dawn to win his race, while in "Easter Lilies" an old maid in reduced circumstances dreams of the wild lilies of Malta she knew as a young woman and summons them, freighted with a secret treasure, into her suburban church. In the marvellous triptych "Telegony" (meaning "the belief that the female can be changed metabolically by a particular lover"), the inner lives of an upright Yorkshire family are laid bare through the fantastical shapes that thwarted feeling assumes down three generations, from its matriarch Florrie Ironside, "taught that you never go out unchaperoned and never show your love", who ends up dead of jealous rage, down to a middle-aged granddaughter silently mourning the passing of sex in a Cremona cafe. Grief, too, the other end of love, breaks through the lovely silvered surface of one story after another, a terrible silent bomb going off in the quiet lives of the widowed and childless. In "Rode By All With Pride", the beloved only child of a stoical pair of Wimbledon stalwarts succumbs to despair, leaving the green garden in which she grew up a desolate wasteland.
Gardam has a remarkable economic vividness as a writer, shown to particular effect in this compact form: she also has a gift for placing beauty on the page and imbuing it with emotion, from "the skyhigh curtain-drops of glittering lights" of Hong Kong by night in the story out of which her prizewinning Old Filth trilogy grew, to the windswept Irish beach where a worn-out mother yearns for lost love. She can also write about sex: the few lines in "Grace", in which Clockie loses his virginity, are a masterclass in deliciously arousing restraint. Born only seven years after the publication of Joyce's Dubliners (which she cites in the introduction as showing her how the short story can "have the power to burn up the chaff, to harden the steel without comment or embellishment"), Gardam is muscular in her approach to the form, too, and unafraid of literary experiment: one story, bubbling with vitality, is written in the fractured speech of an ancient tramp as he breaks into a middle-class home.
The binding power of this collection, however, running like electricity through every story, is magic: its pages are populated by devils and apparitions, mermaids, ghosts at garden gates and green men. There is a boy who turns into a bike and a factory worker born with a diamond in his neck who knows, like his creator, "the ropes of living and dying". "Jane has always had her ecstatic side," her mother once said. As with Joyce's epiphanies – and few Gardam stories lack one – her magic is not whimsy, but utterly integral to her narrative style and her subject matter. It emerges from her shamanistic abilities as a writer and is bound to an instinct for the sacred and the miraculous (in folktale, in myth, in railway carriages at Christmas and in country churches). She makes it at once outlandish and entirely convincing.
It is Gardam's gift for the ecstatic, for showing us what a place of wonders is the world and the hearts that dwell in it, that endows this collection with a dangerous and formidable energy, richer and more concentrated than any novel. She gives us miracle heaped upon miracle, and insists that they should each one be handled with care.
• Christobel Kent's The Killing Room (Atlantic) will be out in July.