Iain Sinclair: Bard of graffiti and broken bottles

Iain Sinclair's latest book takes him to Essex in the footsteps of John Clare. Murrough O'Brien finds out why

For 36 years, Iain Sinclair has lived in the same house in Hackney - the first to be built on the site - with his wife, Anna. He is a big man and Anna, too, has his height and strength of build, and an even sharper aura of spiritual authority. Their creative relationship is deeply symbiotic. She interprets his dreams as future novels, he digs into hers and uncovers history. Sinclair rejects a comparison with Yeats and his wife: "There's no bullshit here. Anna has this practicality, but also this extraordinary vision. She previsions things I'm writing... I needed her spirit to navigate me through the flatlands of the east." Sinclair is a child of mountains and valleys, a lover of Tors and cromlechs. The east interested him little before he came to London, and Essex not at all until he met the ghost of John Clare.

In his new book Edge of the Orison, Sinclair retraces the escape of the "peasant poet" from High Beach Asylum in Epping Forest and his three-and-a-half day walk in search of Mary Joyce, whom he insanely believes to be his wife. But she is long dead, and she was his childhood sweetheart, never his wife. Iain and Anna Sinclair, the writer Chris Petit and a photographer called Renshi follow Clare's footsteps in search of Anna's ancestors, Clare himself and a half-decent pub. The walk gives up its secrets eventually, as the quest for Clare becomes something more like a mission. Shelley, De Quincey, William Burroughs, even Leopold II of Belgium, all dart in and out of the story as Sinclair sets up his loom in the mind of John Clare, searching for new threads, new connections.

We read of Clare "prospecting for words" among familiar fields, and later, in the asylum at Northampton, "sitting there, writing on demand, fearing that words are being pulled from his ears". Sinclair's prose is as pithy as ever, ferociously detailed, endlessly insightful. But he confesses he has no taste for substantial revision: "I don't agree with that perfect, Proustian polish. It's not feasible, it's not even desirable... This is a relentlessly hungry process. I'm just glad if what I write is tolerable, if I haven't made too many howlers."

Sinclair's poet is a reluctant seer, in part "a cunning peasant, quite shrewd, quite 'there'," who nonetheless found "his visionary side painful. He thought of himself as a clown, a freak." And was London the final straw? "I think these three visionary trips to London are the test, again, in terms of his being an initiate." But in the world's terms, he failed the tests. London undid him. As Sinclair says, "He saw a city of ghosts and voices, of Gothic fevers. I think that vision is accurate. And in the end there's no way for him between the two worlds. His soul is lost on the road." This last probably accounts for the fact that, like Shelley, Clare was often the hostage of his visions. Though Sinclair agrees that the poet could sometimes train his imagination to lighten up, he observes: "When the coach is going down to London he has a sense of himself being one of the watchers in the field. Is this a new being split off from his earlier self?"

As he points out in the book, Clare and Blake are two poets with much in common who have rarely been compared in detail. Sinclair suspects that one reason why Clare foundered and Blake triumphed was Blake's very obscurity; being out of the publishing loop, he could not be strangled by it. "You'd think, which of these two is going to be put in the asylum? This guy who's talking to the prophets and seeing the ghosts of fleas, or this everyday farmer's man who can recognise all the birds and animals in the fields - and he's the one who ends up 22 years in an asylum..." A new thought strikes: "...charged with being not visionary enough! If he'd gone over the top and been defined like that, he'd probably have been a public figure!"

Both Sinclair and Clare are united by a keen sense of space and place, coupled, paradoxically, with a wanderlust; ferociously fluent prose; and, above all, what Sinclair calls, "the cataloguing instinct": "But instead of Clare's fauna and flora, I note graffiti, broken bottles, the remains of a TV set." But, in other ways, Clare, he says, "was very much removed from my own instincts and areas of immediate knowledge." Even Clare's place in Sinclair's mythological understanding is uncertain: "When we went to Oxford to see Shelley's watch [an incident recorded in the book], we were shown the manuscript of Frankenstein. And I very much saw the creature Frankenstein made in terms of being a golem. Clare is a golem in a sense, stitched together, created by the publishing machine of the time. But then he runs around through London like a golem with one of the letters wiped out on his forehead... he would like to bring the city down. But he can't. The second part of his life is lived as a kind of cancelled golem, a thing without a shadow, identity worn away - but then, can there be a country golem? It's in the nature of the golem that he's part of the ghetto, part of the city. The spectres of the country are shadows, creatures on the path. There's always a path. Footsteps behind you, spirits of the river, staring down into the river, seeing the land's end." As Clare did, when he saw stars in the abyss of a well.

You can't read more than two pages of any of Sinclair's works without being troubled by a sense of transcendental claustrophobia. What is that unmistakably ancient cadence beneath the modern metaphors? "I can remember," he says, "relatives standing up in Welsh chapels and improvising sermons that went on for two hours, and I'm sure that, written down, they'd have been unreadable, they'd have been incredibly turgid - but because of the force in the preaching, the congregation were gobsmacked. That definitely carried over into my writing."

The Scottish side, his father's, is also deeply important to him: "The Scottish sense of going off, leaving one's homeland; being banished into the world and having to adapt to jungles and deserts. And carrying this culture with you." It comes as no surprise to learn that Sinclair believes London itself to be a Celtic city still, with its mounds and sacred ways. When he left Wales, was he fleeing all that clammy Celticity? "Yes, but also taking it with me to a town which has too many tokens of that inheritance to ignore."

There is no Sinclairian mission, as such, but there is "vocation-curse" and "a contract". A contract with whom? He smiles softly and hugs the air in front of him. "This." Yes, and...? "The spirit of the place itself. Echo-chambers of the voices of London. You have access to them, add something to them... A discovery of a particular place on the face of the earth that would allow me to write. I could not have done this living in Wales, or Ireland." But there are no particular figures leading him on, instructing him. He laughs: "No, no... I don't think there's a godhead of writers watching and waiting and holding out an end-of-term report card."

To order a copy of 'Edge of the Orison' (Hamish Hamilton £16.99) for £15.99, call Independent Books Direct on 08700 798 897