London is a jungle

There is teeming life on every page of this remarkable novel, from crabs running "like pianists' hands along the beach" to pelicans "leering ... with shiny eyes like louche old men at a strip show"; from frightened, shrieking Bedouins in an Egyptian desert to a 25th-century London eerily overrun by tropical plants breeding from Kew and a million deserted living-rooms.

But life, in the final bleak analysis, is nothing more than a vehicle for decay. Beginnings begin in endings, with civilisations revealed as fragile intermediary pyramid schemes. "The trick is to keep wringing new loans from nature and your fellow man," concludes narrator David Lambert, who himself is wringing the last drops of sane activity from a brain riddled, he believes, with "wigglies" - also known as Creutzfeldt-Jakob disease.

Lambert, a Cambridge graduate, archaeologist and naturalist, comes upon evidence left by a geriatric H G Wells that time-travel is not just a fictional construct but a real possibility. Wells believes that his lover Tania has travelled to the future in a purpose-built time machine - and will return in 1999 for Millennium celebrations. She doesn't turn up, but a whiff of her scent left in the recently vacated contraption is enough to tempt Lambert into a voyage of excavation and exploration.

The humid London swamp in which he touches down shows no signs of human life. Instead, skyscrapers have rotted, "their mad wigs and cavern eyes, the sagging steel and triumphant greenery a shocking sight - like finding a person you last saw young and healthy dead in the bushes and decomposed". Lambert's horror, melancholy and fear is at first dissipated by curiosity. Machete-hacking through the jungle, with only a panther by the name of Graham for company, he begins to unearth fragments of his traumatic past and shattered love affair with Anita, an Egyptologist. Skeins from past and present are woven into a surprisingly comprehensive account as he revisits old scenes, reworking old memories, all the while remembering that time is revanchist and that "excavation is destruction".

Several themes are brilliantly adduced in this novel, which draws on the heritage of George Orwell and C S Lewis, Shakespeare and the Bible. The loss of innocence and the adamant nature of time are constantly recurring discussion points.

In the end - if it can be seen as such - it is fitting that Lambert embodies the myth of Tithonus, the doomed mortal who demanded immortality without specifying youth, and was eventually turned into a grasshopper by the goddess Eos. Lambert, similarly agile, is also tragic; his tale absorbing and dynamic, intricately clever but bleak.