The 'grim necklace' of the M25, the 'London Orbital' of poet and novelist Iain Sinclair's new documentary, is as likely a site of pilgrimage as any other, if - like Sinclair - you do not trust received cultural mappings. You walk out into the culture and gather what the walking throws up, the motorway's acoustic footprints pre-echoing your own. Keep jotting, looking, snapping, listening, digging into local histories. (The book foregrounds its methods of recording.) Back at base, consult the reference works, orthodox and otherwise, paste the quotations in. Check citations. Occasionally re-visit the sites. Re-configure the cultural ley lines you've drawn. This mix and method produces a disjointed text, but it is readable, rich, and ridiculously funny. While it nominates its cultural heroes - the 'reforgotten' writers and artists of the recent past - it is clear who its demons are. The powers of darkness are all too human, the Tory privateers and the New Labour spun-dry rhetoricians. Sinclair locates them at the Millennium Dome, whose Blakean annihilation is the aim of the anticlockwise circumnavigation.

To attempt this pilgrimage on foot is perverse (you cannot get on the road) but logical; Sinclair rejects the postmodern strategies of Baudrillaudian tourism: the flâneurhood of the windscreen blur, the homemade road movie of the commuter. (The road's own postmodernity is asserted by its circular selfreferentiality, we are assured.) Sinclair and his troupe of comic anti-heroes adopt the ancient guise of the wanderer, the less sane perambulations of the fugueur. ...