David Harsent's 10th collection can be read almost like a novel in that most of the poems belong to a continuing world. In other ways, this could not be less like a novel. It demands re-reading. The experience is like setting out on a journey at night: your eyes take time to get used to the dark. These are among the most frightening poems I have ever read. It does not come as a surprise to learn that Harsent once wrote crime fiction. But it would be misleading to say his poems are frightening in the way a thriller is. They are far more enigmatic, unburdened by plotty reassurances and free of resolutions. Harsent creates a suspense that has no ending. His poems have something in common with the novels of John Banville  especially The Book of Evidence  in that they describe a world charged with emotion, stained with shame, in which nothing is neutral and where lyricism thrives but can never absolve. As in all the worst nightmares, even the light turns out to be frightening.

The narrator has evicted himself from his former life. In the opening poem, "Rota Fortunae", he writes: " and there floods in, now as never before, that sense/ of giving yourself over to chance/ that will turn you for home, or take you to the brink". By the last poem, the sun has taken fortune's part: "the sun going down like a broken wheel;/ and everything at my back". The poems create an unreliable landscape in which only the sea can be depended upon to be itself (and is brilliantly written about  "the sea gone white/ as if water could run under frost"; the simple beauty of that idea stops one in one's tracks). Nothing is steadfast, and the sky is prone to strange exhibitions of colour: "do whatever you must, so long as that purple-and-yellow blush/ in the sky doesn't mean what it seems"

There are many roads  more and less travelled. Night overwhelms day. In "The Garden Hammock" (see below), night advances with startling speed to cancel out a summer scene. All the garden poems are wonderful and strange. The houses in this landscape haunt themselves. Rain is always on the cards. And the cards, when consulted, augur badly. There are many dawns, most of them false.

The poems pursue a solitary journey in which a woman is sometimes sighted but unreachable, as if seen from another world: "A woman is laying a table; the cloth/ billows as it settles; a wine-glass catches the light." But these poems do not need personal effects, names, faces, birthmarks. Harsent has a dreamer's eye and an unerring ear. He has a gift for finding last lines that know they must be the last. "Vanitas" ends with an ostensible irresolution that turns out to be conclusive: "what happens next is anybody's guess:/ the window a mirror perhaps, the room a wilderness". One wants to speak this aloud for the pleasure of its final rhyme  the way the three syllables in wilderness extend themselves so that one can lose oneself in the word.

"Elsewhere", the long poem that ends the collection, is Harsent's most dazzling achievement. "Elsewhere" might be the title of the entire collection in that it extends the exploration of what it is to be transplanted, on the run. This poem deepens the theme of dispossession, the days and nights of reckoning, the consideration of what it might mean to lose everything. Harsent alludes to loss in so many ways but his poems are treasures  all gain.

The Garden Hammock, by David Harsent

Your book is Summer by Edith Wharton. A smell

off the borders of something becoming inedible.

Between sleeping and waking, almost nothing at all.

There's music in this, there would have to be: a swell

of strings and bells becoming inaudible,

note by note, before you latch on to it. The girl

in the story won't prosper, that's easy enough to tell.

How did night come on like that? The sky is full

of birds, wingbeats in darkness becoming indelible.

"Is it wrong to be so addicted to grime and grief?" asks the insomniac in the title poem of David Harsent's 10th collection, Night. The poem immediately answers him: "Perhaps; but he'll see this out." Harsent's work prides itself on staying open to a wealth of violence, suffering and seediness, without blenching or losing consciousness.

Legion, his last volume, which won the Forward prize in 2005, spoke from an imagined war zone; Marriage (2002) gave an uncompromising study of intimacy and desire. Night brings this darkness indoors and inward to the realm of the "troubled mind", where "the mad machine cranks up / and the room breeds shadows out of dusk".

Loss is the abiding theme: lost bets, lost loves, lost light. Narrators squint, "cock-eyed", trying to make sense of the smudged forms in their suburban gardens. When night falls, there is nothing to see outside but your face in the glass. Memory becomes the centre of dramatic action  "limitless memory starting up in the dark"  although it's often unreliable. A man wakes up on a beach with no idea how he came to be there; another endures glimpses of a sunlit past he couldn't protect.

The heartbreaking "Blood Alley", ostensibly about a prize marble, soon arrives at what seems to be the memory of an abortion. Here it is in full:

"Your childhood token, a sickle of red in the glass, albino eye, / eye of the night-lamped hare; a perfect lob would break the circle . . . // Now hold it close to the light and every fibril / seems to shred, as heart-blood hangs in water, that same dark dye  // shade of the dress she wore when you had your first full taste / of the pulp of her lip and the spittle off her tongue, the cost // to you being more than you had to give, which is why / the circle must break again and the dream unpick and the child be lost."

Harsent's lines are incredibly supple, stretching and looping, snapping back, never coming unstuck. He is formal in the sense of being highly conscious of musical patterns, but his patterns are roomy and irregular, playing shape off against shapelessness with expert improvisation. Rhythms are syncopated; rhymes tend to be half or slant, and unbalanced by internal counterparts to give an off-kilter, off-the-cuff effect. It's an unmistakeable, endlessly adaptable style, able to hit every tone on the scale, from leer to lament.

The long poem, "Elsewhere", which ends the book, infuses the stiff didactic form of a medieval morality play with thrilling moral ambivalence. Haunted by the woman he abandoned, and led by a skinny, feral dog, the narrator travels through the imaginative landscape of his life. We understand he is really in his bedroom, drinking alone, but the literal facts of the journey matter much less than its shifting moods, layers and characters: a floozy in a bar, a fortune-teller, a "sad old sack" living rough on the beach.

When a mannequin in a shop window with "anglepoise wrists" (Harsent is brilliant on people "positioning" one another) steps down into the rain to speak to him, she stirs memories of "that room, the deepening dusk, the square, some madcap swifts / circling the Palace of Delights and the rotunda", before interrupting his reverie: "'Why is it,' she asks, 'that memory never adapts / or softens or finds peace in forgiveness?'  The wind shifts, / birdsong turns sour, the snapshot blurs and fades, another blunder / leaves us out on the edge, a cold night coming on, / some rawness on the skyline like a wound / puffing and purpling. Are you proud of yourself, I wonder . . ."

That self-directed question, "Are you proud of yourself?", marks a devastating switch in tone. He is proud of his wounds (doesn't pride puff and purple too?), and of the wounds he has inflicted on others; like Everyman he seems to be in search of absolution, but when the chance comes he is never prepared to release his grip on the past.

In Harsent's perpetual face-off between the sacred and the profane, the sacred usually blinks first: "The Queen Bee Canticles" shows us the priest of a Norman church transformed into a "spinning ball of bees", their queen "so thrilled with his passion she stung / his lips, his tongue, his eardrums, his eyelids, his eyeballs".

Harsent's translation from an Old Cornish mystery play, The Creacion of the World, also features an unrepentant speaker. When Cain, in the form of an animal, is shot by one of his own descendants, he uses his dying breaths to explain how he feels about murdering Abel: "Although I lie here at your feet / speaking through blood and bile, I don't regret it; / each night I dream of even blacker fame, / then bad luck wakes me and I rise to greet it."

Harsent's characters would always rather brag than appeal, but behind their braggadocio is an equally vulnerable wish to impress, and to survive in a world where appeals tend to be met with indifference, even scorn. "Tell me again," says the floozy in the bar, "how you wrung her tears from your shirt, how her pain / was the little light you carried to find your path / after nightfall . . ."

Pain and loss light us through the darkness, Harsent insists, as well as contributing to it. The light of these poems is essential.

Frances Leviston's Public Dream is published by Picador.