Psycho-geographers are inclined to take themselves rather seriously, but not Tim Bradford. Owing more to Spike Milligan than Iain Sinclair, this serendipitous set of descriptions of walks follows the traces of London's hidden rivers. It also describes a compulsive interest in London's punk and pub scene circa 1980, and other outstanding guilt trips of the author. Some of it is very funny, though the quirky drawings and cartoons don't always have the effect intended.

Yet all the basic information is here, about the New River, Hackney Brook, Dagenham Brook, the Fleet, the Effra, the Ching and many other ancient rivers and streams. They were either culverted, canalised or buried underground, where today they exert an even more disturbing power on estate agents than they do on dowsers or local-history buffs.

In some ways, Bradford wears his learning almost too lightly. Casual readers may think at first glance that there isn't very much historical or topographical substance, when there is. Not only is there a considerable amount of fascinating material about London's riparian history, but the reader also gets a convincing series of snapshots of the contemporary streetscape of the capital's urban canyons and arteries, its parks and cemeteries, beyond the over-familiar West End. Occasionally, a reliance on internet research - where obsessive localists are often responsible for a great deal of unmediated misinformation - shows through. And some jokes wear out quickly. There are a number of running gags about online dream analysts, Dr Johnson's escapades, Danish punk music, feminist river-worshippers and the author's predilection for various types of industrial-strength lager.

Unusually, despite the bizarre admixture of styles and preoccupations, Bradford is not an unreliable narrator. His likeable transparency and topographical sense of detail and accuracy are engaging. The book, however, is too long, and towards the end one feels that the narrator, unlike the rivers he describes, is beginning to go round in circles. Spike Milligan rightly made a virtue out of writing very short books. Quirkiness does not go long distances.

There is also a tendency to laddishness, even if it is self-critical, and too many references to football teams, punk bands, run-down pubs, and an occasional sense of nostalgie de la boue (a peculiarly masculine literary affectation), which some may find off-putting. Others, especially those who were not only around London's punk scene but can also remember it, will find the evocations of raucous scenes in rough pubs knowledgeable and sympathetic. The Clash, of course, made one of the great apocalyptic records about London's rising rivers and waters (and much other social mayhem) in "London Calling".

Such connections between literal and metaphorical underground currents, burrowing away in London, is at the heart of the author's interest. Read in small bursts, The Groundwater Diaries have the wit, energy and attitude of punk music itself, which was also not without serious cultural importance and even occasional beauty - as well as distinct affiliation to a phantasmagorical London sense of place.