One might be forgiven for thinking that the only thing more boring than spending a year walking around the M25 would be reading a large book about walking around the M25. Yet Iain Sinclair's London Orbital is a fascinating and curiously haunting read. Part of the reason is that Sinclair brings to the project an immense literary talent, an intense and lifelong interest in the history of London and some extremely interesting travelling companions.

The walk was taken in several stages, from Waltham Abbey to Shenley, Abbots Langley to Staines, Staines to Epsom and Epsom to Westerham before going on to Dartford, the river and Carfax and arriving back at Waltham Abbey. Each stage fills a chapter and the reader is advised to take a leaf out of Sinclair's own book by taking one stage, one chapter at a time. This is a large book of 450-odd pages and by the time the journey gets under way-–about 60 pages in--even Sinclair's dazzling prose is not enough to offset the gloomy prospect of taking a second-hand trip around the London Orbital. And yet after the first trip one finds oneself being sucked in and thinking about some of the grey, ugly images, or being angered by the grasping and philistine approach of developers and copywriters and the cynicism and hypocrisy of government.

The history of London has long been Sinclair's great passion but he populates this strange excursion with flesh-and-blood people as well as literary and mythic figures: there's John Clare watching Byron's funeral procession before embarking on his epic three-day journey back to Northborough, "chewing tobacco and gnawing grass torn up from the roadside"; then there are tales of Dracula, of lost lunatic asylums, of passionate political activists crying out against toxic land and of meetings with ex-members of London's criminal underworld.

London Orbital gets under the skin. What looks at first like a dull and deeply unappealing journey is actually a multi-layered, lyrical, ugly, mythical, engaged and engaging excursion from the present into the past and back again.

London School of Economics - opposite the Peacock Theatre - Ground Floor - Confucius near the Chaplaincy say look carefully and you will be rewarded for your patience....