Ordinary Thunderstorms, By William Boyd

A man newly arrived in the big city makes a brief acquaintance with a preoccupied stranger. The next time they meet, there's a knife sticking out of the stranger's side. Our hero scarpers, leaving incriminating clues, but finds there's a ruthless assailant outside his home. Soon he's on the run, both from the police and some unknown malevolent organisation which is out to get him, unless he gets them first...

Yes, it's the plot of The 39 Steps by John Buchan, but also the opening pages of William Boyd's new novel. Boyd is, of course, one of the leading lights of the Amis/Rushdie/McEwan generation, and the author of Any Human Heart, a subtly brilliant, diary-based chronicle of a 20th-century literary life. So there must be more going on here than a simple, innocent-man-on-the-run thriller. Luckily, there are literary hints and allusions galore.

The smug boss of a pharmaceuticals company is called Ingram Fryzer, the name of the conman and spy who stabbed Christopher Marlowe to death in a Deptford tavern in 1593. The fictional Fryzer's business is being taken over by a Brazilian corporate raider called Rilke - a nod to the lyric poet of the Duino Elegies. A young policewoman called Nashe (after Thomas Nashe, author of The Unfortunate Traveller and – significantly – a spoof book about red herrings, published in 1599) lives on a barge called the Bellerophon, after the Greek hero who tried to fly to heaven on Pegasus the winged horse.

You convince yourself, for a while, that a clever post-modern spoof is under way. But this is a thriller pure and simple. There's a complicated plot about a new wonder-drug that will cure asthma, but whose effect on young patients during its trial is a little too final. Its manufacturer will stop at nothing to preserve this awkward secret.

Our hero on the lam, Adam Kindred, encounters a vivid cast of ne'er-do-wells and down-and-outs in his travels. He holes up on a nasty estate in Rotherhithe with a young black prostitute called Mhouse, who keeps her son Ly-on quiescent by lacing his cereal with slugs of rum and ground-up Diazepam. Adam finds solace in the Shoreditch HQ of a crackpot religious sect, inhabited by friendly illegal immigrants and furtive English paedophiles. On his trail is the scary Jonjo Case, a large ex-SAS psychopath who loves his dog, hates blacks and employs horrible methods to ensure the co-operation of victims.

There's a strand of pure boy-girl romance between Adam and the policewoman who pilots a riverboat. Some of the minor characters are lazily evoked – like a Harley Street doctor called Hamish McTurk whose Scottishness is announced by his way of offering patients a "wee dram" and saying "You'll have had your tea."

The narrative bounces along grippingly, though, alternating chapters about (and in the voices of) the pharmaceutical fat cat, the drug dealers, the hitman, the hooker, the cops, the church and the runaway, tacking back and forth from Chelsea to Canary Wharf, taking in a dozen London sites. The metropolis becomes a character, in its sprawling, baggy anonymity.

If the novel has a central theme, it's identity and its opposite. In having to abandon his home and all the electronic paraphernalia that could give him away (from mobile phone to pin number) Adam becomes an existentialist cipher. He turns into other people. His name changes from Adam to "John 1603" to Primo Belem. His address becomes a patch of waste ground in the heart of Chelsea. He becomes one of "The Missing" about whom Boyd is eloquent: "Two hundred thousand missing people – and most of them would be in London, he reckoned, subsisting, like him, under all the categories of social radar – living underground, undocumented, unnumbered, unknown."

Boyd emphathises convincingly – this book offers helpful tips for successful begging – but never seems overly concerned with the larger picture. Like Sebastian Faulks's A Week in December, Ordinary Thunderstorms features the London Eye on its cover, but Boyd isn't attempting a condition-of-England novel. He merely says: look what happens when you disappear from the world that gives you a role. It's a little disappointing.

The title, and Adam's profession of climatologist, seem to promise a tsunami of weather symbols, suggesting the socio-financial storms that threaten British society. They never appear. The only detail we learn about Adam's climatological past is that he once had sex with a student in a cloud chamber. Like so much in this book, it promises a lot more than it delivers.