SWITHERING, the title of Robin Robertson's new collection of poetry, is one of those useful, beautiful Scots words which has no exact English equivalent. It has various meanings, the primary ones being uncertainty, confusion, indecisiveness. But swithering can also evoke a state of fluctuation, of flurry, of what Robertson identifies as "flux". In that sense, a switherer is someone or something perpetually in motion, like a sea "scalloped/in marbled endpapers of green and blue and grey".

Over a pot of tea in the dimly lit bar of a Covent Garden hotel, Robertson picks his words as carefully as a poet will. He turned 50 last year, but Swithering is only his third collection of poems. One reason for this, he says, is that he started late. His first collection, A Painted Field, was published when he was 40. Half a decade later came Slow Air. As he grows older, he jests, he is picking up speed. "I calculated the first book took 15 years to write, the second took five and this one has taken four. At this rate I'll be doing a book a week ."

Another reason why he has published relatively little is the nature of his job, which is arguably the least conducive to being a writer. Robertson is deputy publishing director of Jonathan Cape, one of the country's foremost literary publishers. The list of novelists and poets for whom he acts as editor is formidable: Irvine Welsh, AL Kennedy, Michael Longley, Janice Galloway and Alan Warner. As day jobs go, Robertson's is clearly more mentally draining than most.

"To be an editor of fiction and poetry, " he says, "the point is to work closely with the writer on the text, and if you're going to be any good at all you have to try and find yourself inside the speech patterns, the prose rhythms . . . You can't go home at the end of the day and think, ah, I'll write a poem now, because you've got that kind of sound pollution, if you like, from someone else. And also, I spend a lot of time reading. To be any kind of writer you have to have solitude and so I would find the only way I could write was to go away to a retreat of some kind. They're generally rural."

The influence of where the poems were written is obvious. Ironically, for a poet who has lived most of his adult life in London, Robertson is insistently interested in nature. With a couple of exceptions, he is in thrall to the natural world, realising in words what many take for granted, "a glut of dew", the "edging wind" that "eats everything". In contrast, Entropy, one of the few poems with a metropolitan backdrop, is an expression of anxiety, of the hurl and burl of "eight million magnets/repulsing or attracting, hackled like attack dogs/or hot-wired to this smear of light and speed, /gunning the gas". By the end, the poet is "on my knees in the dark".

Like most poets, Robertson is no celebrity. Nor is he ever likely to be. These days writing poetry has been marginalised, even by the chattering classes. "The intelligent, tertiaryeducated professional, who reads the Booker Prize winners, reads some decent nonfiction, reads the broadsheets, wouldn't dream of reading a book of poems, " says Robertson. "What's happened here is extraordinary. Somehow it's not important enough. You can get through a dinner party without having read the new Simon Armitage or the new Paul Muldoon but if you don't have something to say about the new Ian McEwan or whatever, it's a cultural flaw."

Nobody, says Robertson, can earn a living from poetry, though in fairness few ever did. Only three poets, he reckons, sell in quantity - Seamus Heaney, the aforementioned Armitage, and Carol Ann Duffy. A first collection of poetry might sell 600 to 700 copies, an established poet with five or six collections to his or her name around 1500 copies. "It's very tough out there, " he says.

Nowhere is this more apparent than in bookshops, where poetry, like literary fiction, is often treated as if it were a bad smell. "Try looking for it in your local Waterstone's, " he says. "The days when you could walk into a shop and have an informed, intelligent member of staff help you out, when the manager was a maverick, knew his staff, knew his stuff, that's all gone. You have to wade through all these three-for-two offers."

If that makes Robertson sound like a whinger it is misleading. He is simply stating facts. Sure, there was a time when poetry was popular but that has not been the case for decades. What does seem to have changed, however, is the public's perception of it. In Scotland, for example, which boasts the first Unesco World City of Literature, it is bestselling novelists who are regularly name-checked and trumpeted, not poets. It's a far cry from the days when Hugh MacDiarmid, Norman MacCaig, Sorley MacLean and others were revered as the heirs of Henryson, Dunbar and Burns.

Robertson was born in Scone but bred in Aberdeen, where his father, a Church of Scotland minister, was first a chaplain at the university, then the warden in halls of residence. He was, says Robertson, "a wonderful man, absolutely wonderful". He is the dedicatee of Slow Air, a book blue-veined with grief. The poem These Days describes his dying, in the wake of which the poet can hardly walk, he is so frightened: "These days are scored through, one by one. /The wardplan wiped clean for another name; /another man lies in the bed behind the glass. /My mother struggles with the singular. /We must all learn to use another tense: /the past."

In contrast to so many children of the manse, Robertson was not "force-fed" religion. Nor has he ever had any faith. But he did like watching his father preach. "I suppose what I took from my dad was the cadences rather than the creed; that wonderful rhetorical power of scripture read well and sermon that actually made sense."

He studied English at Aberdeen, then went to Canada where, in Windsor, Ontario, he had the good fortune to be the teaching assistant of Alistair MacLeod, the short story writer and novelist, whose publisher he now is. From Canada he applied for a post with Penguin and thus entered publishing. In 1997, A Painted Field appeared, garnering effusive praise plus the Forward Prize for Best First Collection and the Saltire Society Scottish First Book of the Year Award. It ended with an ambitious sequence called Camera Obscura, a poetic rumination on the "catastrophic" private and public life of David Octavius Hill who, together with Robert Adamson, pioneered the then infant art of photography.

Hill was an indifferent painter, who resolved to commemorate the 1843 Disruption, which resulted in 400 ministers leaving the established church. In order to capture their likenesses accurately, Hill set out to photograph them all. Subsequently, he and Adamson set up a studio at Rock House on Calton Hill, and for more than four years produced a phenomenal body of work which is internationally regarded as the finest of all early photography. Adamson died in 1848 and Hill abandoned photography. But he continued working on the Disruption painting, which took 23 years to finish. It was, as Robertson says, "an abject failure". To compound the tragedy, when Hill died in 1870, there was no mention in his obituaries of his formative work in photography.

For Robertson, Hill's story is Scotland's in microcosm, that of a man who did not understand at what he was truly good and who was unacknowledged in his lifetime and uncelebrated in death. It is also a poem about longing, a requiem for lost potential. But then, as the poet says, "aren't all poems, poems of longing?" Certainly, that is true of many of Robertson's, in one of which, he writes about "an emulsion of longing". Which, now one comes to think of it, seems to neatly sum up where he is coming from.

Swithering is published by Picador, pounds-8.99