What is Iain Sinclair up to? Or, put more pertinently, what is he on? He is at an age when, with any justice, he should feel himself to have reached a literary junction, and be prepared to coast through it, before taking the slip road down to banality, or senility, or even - heaven forfend! - the acceptance of those gongs indicating that the Important Writer complacently anticipates posterity. But Sinclair, far from winding it down, is cranking it up. Like some compositional machine, he spits out poems, collaborations (with the photographer Marc Atkins, with Rachel Lichtenstein on the acclaimed Rodinsky's Room), novels, and even a definitive critical study of J G Ballard. Now comes London Orbital, the second big chunk of paper sculpture in six years, a complex womb of ruche and fold and pleat, designed to encompass his earlier work of crazed cartography Lights Out for the Territory (1996).
Could it be that he and Peter Ackroyd, his fellow London mythographer, are pacing each other towards an untimely grave? (I recall Ackroyd, encountered by chance at some lit'wry powwow, puce, pre-infarct, cheerily apoplectic, inveighing against Sinclair: "Of course, he nicked it all from me, you know, the whole thing!") But the whole what, exactly? London? Writing about London? Walking around London and writing about it? Making the interplay between a progress around the city and the progress of your narrative - as you leap from one anecdotal paving stone to the next - the very gubbins of a text? I think not - on all counts. After all, none of it was theirs to own.
Still, it is possible to see why these two great writers might come head-to-head over the corpus delicti of their muse: both of them have taken the aimless saunter through the city and shaped it into a vigorous literary form. Both of them love London - Ackroyd with a native son's desire to lay his head on her stony breast, Sinclair with the wide-eyed romanticism of an incomer from the sticks. And both of them have a peculiarly English (although in Sinclair's case there must be a Celtic residuum) take on mysticism, which is conceived of as a DIY guide to transcendence, the bricolage of the bardo.
Sinclair openly styles himself as a "psychogeographer", but what does he mean by this? The concept has a literal meaning for Ackroyd: the city conceived of as an analysable persona, the very spirit of the Thames Valley beehive. But it's strange to see what different - and yet complementary - uses the two of them have made of their French inheritance. The situationists of Left Bank Paris undertook their derives in an altogether aimless fashion. These urban rambles, guided by Guy Debord, a pisshead mystical Marxist intellectual manque (presumably holding up a cheap bottle of wine, the way a London tour guide lofts an umbrella), were aimed at deconstructing the urban space. The cities - according to these filthy flaneurs - had become merely factories for the production of soullessness, and it was their duty, by lying about drunk on the Ile de France, to liberate Paris from its collective obsession with work, consumption and industrialised mass "leisure".
But across the Channel and 40 years on, Sinclair has made of psychogeography an altogether more productive, if decidedly less millenarian, field of study. While Ackroyd is a shameless antiquarian, a John Stow de nos jours who stomps through time and space kicking up the fossilised imprints of styles and modes, Sinclair, on the other hand, has at least a half-belief in full temporal simultaneity. On his epic progress around the M25 orbital road, Sinclair marks certain events - such as "the Brink's-Mat alchemist" Kenneth Noye's "road rage" killing of Stephen Cameron at the Swanley interchange in May 1996 - as "gates that act as circuit-breakers, disturbing the energy generator that hums continually around the undisciplined body mass of London". Such phenomena may provoke hallucinations that are nothing of the sort. Here he is writing of a Museum of London exhibit that juxtaposes an Iron Age village with Heathrow Airport: "Rub your eyes and thatched huts break through the tarmac. Neither description is definitive; one state of consciousness bleeds continually into another."
But the reader senses that Sinclair is, quite simply, too grounded to ritualise these queasy intimations. Or, rather, that the act of walking-as-writing that constitutes London Orbital, and his other works of urban trolling, is sufficiently ritualised in and of itself. He needs no arcana except for metaphor: "The trick was to move back, step away, treat the road as a privileged entity, a metaphor of itself." And once this is achieved, every aspect of the city can be conceived as magical, and all trails undertaken through its living substance are capable of being read as Nazca lines, or cabbalistic signs, or ley lines, or whatever.
So Sinclair writes of "the Turner Axis", or the "Canaletto Axis", and marks the queer fact that "the guns of the battleship [HMS Belfast] were trained on the only (at that time) service station on the orbital motorway". Which leads him to the confident assertion that "the arc of fire represents another of London's invisible threads of influence". For Sinclair, the M25, because it connects so many fringe or marginal places (he adopts Burroughs's coinage "interzone" quite rightly, given that London has more interzones than most cities), completes the final disappearing act of the 21st-century conurbation: "there is no there".
The ostensible reason for Sinclair walking around the route taken by the M25 is to exorcise the malevolent influence of Richard Rogers's Dome, that millennium party hat for Big Nobs. He inveighs against it as "an alien form; a spoiler. It ruined the low-level riverscape, the dingy mystique of Bugsby's Marshes. It looked like a collapsed birthday cake from the now-disappeared bakers on Kingsland Road, a special order. Yellow candles in a mound of icing sugar. It sagged. It should never have been left out in the rain."
He does not walk on the road itself: that would be as insane as trying to walk along the B2115. Rather, he progresses from his Hackney fastness up the Lea Valley (familiar to Lights Out readers) and then plaits his way along the six - and sometimes eight - carriageways, moving in and outside the orbital road to create narrative French knitting. And what rich pickings there are for him: the Lea itself, with its quango-leisure park and munitions-contaminated island, is succeeded by the environs of Enfield, where grand country estates have ended up as conference and garden centres, their ha-has now only sarcastic laughter. Heading further west, Sinclair and his companions enter a diseased zone, where Shenley (once the haunt of R D Laing) and Claybury cater to psychic turmoil, and Harefield to heart trauma. He waxes eloquent on the transformation of this redbrick badlands into "Barratt estates designed as novelties: protected enclaves with no memory".
The transformation of the past into the present is a recurrent theme, but Sinclair is no stooge of English Heritage. He maintains a value-neutral perspective on the whole business, remarking only on the similar fates of these mega-asylums. Roman Polanski's Cul de Sac transformed into all too real cul-de-sacs. By the time he has worked his way around to Epsom in the south, he finds another hospital designed to the same pattern by Thomas Hine, the architect who was also responsible for Claybury in the north: "European detail on a Soviet scale. Local, sour mustard, London-stock brick. And lots of it."
There is a hell of a lot more in London Orbital. There are potted histories of everything from Uxbridge to Wentworth and back again. There are biographies of William Harvey and General Augusto Pinochet. There is a lot of botany, much of it courtesy of poor Tony Sangwine, landscaper by appointment to the Highways Agency. Sinclair also devotes generous chunks of the book to those he regards as pivotal influences, the seers of London's periphery: J G Ballard at Shepperton, balanced by Samuel Palmer in the Valley of the Darent. Dracula at Purfleet, balanced by Ronnie Laing back at Shenley. He investigates the genesis of the road itself, born from the imaginations of such implausible planners as Ford Madox Ford, as much as from the drawing boards of the authors of the London Plan.
All the way around, Sinclair remains at pains to clarify exactly what it is that he's on about, what this thing he is doing actually is. And with Samuel Palmer's example, he thinks he has found an answer. In contrast with his contemporary, Blake - whom Sinclair accuses of having "visitations from the mythic dead . . ." - Palmer's method was "the walk, the journey out . . . If he pushed hard enough he would surely arrive at the Valley of Vision. It was there to be found - beyond Forest Hill and Bromley. Visionary Tourism. Of the kind we practised; linking place with place, going with the drift, meandering through burial grounds and gold courses."
Yet, having been secretly laughing at Sinclair's hippy-dippy pretensions as he perambulated, when he arrived at this self-deprecating coinage, on page 347, I wanted to shout: "No, no, you sell yourself short!" Because such is the intensity and the lustre of his prose, that Sinclair begins to achieve the occult task he has set himself. London Orbital is so very big, that it makes the Dome seem as small as any very big thing can be.
Mostly absent from London Orbital, except brought to life from others' accounts, or elevated to the status of hieratic figures, are people. Sinclair doesn't "do" people. Or, to be strictly fair, the only people he does properly - and these he does very well - are his companions, his fellow "Ancients", stomping the verge with their clay pipes and impedimenta. In Lights Out he had his faithful photographer, Marc Atkins, snapping at his heels, as well as unsettling writers such as Stewart Home, scary poets like Aidan Dun, and scarier artists like Brian Catling. In Orbital, Sinclair has the near-constant company of his old friend Renchi Bicknell, a mystic dauber and sometime careworker, but Bill Drummond, late of KLF, drops in for a few miles, as do the critic Kevin Jackson and other assorted waifs and strays. Sinclair reprises the oeuvres of David Jones, Chris Petit and Patrick Keiller.
Sinclair loves his companions. He describes them and, more especially, their creative work with accents of love, and, in so doing, tries to bridge the gulf between them and him. But Sinclair is a fellow-traveller of cranks and eccentrics, rather than being truly one of them, just as he is a champion of avant-gardists, while he himself has the tougher, nobler calling of acting as a gateway between them and the mainstream. He himself understands this, writing in London Orbital that "we allow ourselves to become identified with those we promote, so that the manufacture of another writer's biography is a gloss on our own".
Sinclair lacks the true vanity required to be avant-garde in a world where there is no longer any genuine notion of cultural opposition, merely a sense that - as he himself remarks - "present neglect supports elective obscurity".
Pounding his way through the windswept precincts of poetry, and now jogging along the verges of English prose for many miles, Sinclair has reached his own Swanley interchange. His recent work represents some of the most important in contemporary English letters - because of its vigour, its inventiveness, its rugged belief in the metamorphic power of metaphor itself, and most of all its willingness to engage head-on with the clamorousness of the contemporary. My hunch is that he'll tuck his head down, shift his pack on his back, and keep right on.
Will Self's latest novel is Dorian (Viking)