Houses of Memory and London's Orbital Motorway (Iain Sinclair's George Orwell lecture at Senate House, Birkbeck)

A mixed crowd of heavy-coated academics and younger and hipper things assembled to hear psychogeographic shaman Iain Sinclair hold forth.

Senate House in the rain, a Friday night in January: floodlit and looming. A mixed crowd of heavy-coated academics and younger and hipper things is here to hear Iain Sinclair give this year's George Orwell lecture, on 'Houses of Memory and London's Orbital Motorway.'

Following the lukewarm reception that met his latest novel Landor's Tower, the M25 project is awaited with mixed feelings. Sinclair has 'done' London so effectively in the last decade, infecting the culture and sowing seeds that have sprouted in everything from the current Johnny Depp movie (From Hell) to Peter Ackroyd's Hawksmoor, that it is hard to know what is left. And what's he doing here, in the halls of academe?

His territory is more marginal: poetry in haunted lofts, out-of-the-way bookshop readings. Command of an audience comes naturally to Sinclair: we are expectant, and his sonorous drawl easily fills the hall.

As Sinclair begins to talk, the room darkens and Petit's drifting, fragmented and colour-saturated camerawork is projected onto the central screen. Traffic, endless traffic, in daylight, in dusk, in darkness; human figures scrambling uncomfortably over grass verges, alien against the road; Sinclair gesturing and pointing at a map in which pins locate key sites; a woman investigating a mysterious building. It's as if a surveillance camera had been unbolted from its bracket and cut loose to drift according to its own will.

Sinclair and his companions' mission was to walk the M25, widdershins, starting at the meridian and finishing at the notional epicentre of the road's deformed disc, the Dome, on the eve of the millennium. But as always, it is the abandonment to the process that matters more than the destination. Sinclair's obsessions themselves come looping back to meet him, as if he were the eye of some serendipitous tornado. At Potters Bar he discovers the grave of Nicholas Hawksmoor (Lud Heat) yards from the path of the motorway; at Claybury the asylum where Whitechapel mystic David Rodinsky (Rodinsky's Room) was taken; and at Waltham Cross, the starting point of the mad poet John Clare's 3-day 120-mile trek back to a fenland home that had long gone. He even brings in Orwell himself, returning as a down-and-out from France to Tilbury, learning the long meaningless walk of the tramps. Where driving the M25 is a state akin to trance, walking it is a fugue, a sudden resurgence of memory.

And even here, on the fringes of London, the belt that encircles it, memory takes on a subversive character, as the corporate erasure of history and the sterilising of location are pursued with all the vigour that they are in inner London. Ringing the motorway are redbrick towers, all that is left of hospital colonies and asylums, now being turned into Barrett and Crest estates in an arc defined by the optimum commuting time. Where the 'displaced of Whitechapel' were sent to be isolated from the city (and the city isolated from them), their memory is now being erased as developers casually burn the hospitals' records along with their fittings. Claybury, where once the mosquito chamber treatment was used (inside a hermetically-sealed room, malarial mosquitoes are released one by one to infect the patient; the fever 'cures' the paralysis of insanity) has now become Repton Down, spoof gothic, 'elective amnesia' only 35-minutes from Liverpool Street.

Such horror, such memories, can barely be held within the atmosphere and location, the relative safety and sanity of Bloomsbury. When the talk and questions are over, we step outside to the tables lined with wine glasses, but sidestep the crowds and head to the basement, whose walls are lined with maps of London. The largest, taller than head-height, still fails to hold all of the orbital motorway; the North-East slips off the edge. Despite encircling us all, it's remote and mysterious: a road to nowhere.

Danny Birchall <Danny.Birchall AT bfi.org.uk>