The House of Silk, By Anthony Horowitz

It seems improbable, if not impossible, but it's true! Holmes is back at his best

Sherlock Holmes is more than a brand, he's an industry.

Soon after 1891, when "The Adventures of Sherlock Holmes" first appeared in The Strand Magazine, a host of rivals and imitators sprang up, and their flow has never abated. Other detectives, notably R Austin Freeman's Dr Thorndyke and August Derleth's Solar Pons, became respected in their own right. Meanwhile, tales were being spun around every minor member of Conan Doyle's cast. Letters were sent to Holmes from all over the world. The Abbey National, whose building shared the detective's 221b Baker Street address, paid someone to answer the letters, and liaise with the local police concerning the ones in which vulnerable folk or children had asked for help.

With all of this baggage, how can anyone tackle an "official" new adventure with a straight face? Anthony Horowitz, whose book is endorsed by the Conan Doyle Estate, solves the dilemma in the most direct manner possible, by writing a terrific mystery whose hero happens to be Holmes. But he also manages to channel Conan Doyle with uncanny accuracy, knitting together a much more satisfying full-length adventure than, say, The Sign of Four.

It's an untold story retrospectively allowed by Dr Watson, in which the great detective is consulted by a Mayfair picture dealer haunted by an American hoodlum seeking revenge. From the earliest stages of the investigation, there are puzzles within puzzles. Why did an old lady die? Why did four Turner paintings burn? Why should a dead urchin be marked with a white ribbon? Grim warnings surface about the titular house. Its existence is so secret that even the great Mycroft Holmes, never known to heave himself from his armchair at the Diogenes Club, comes to Baker Street with a dire warning: stay away from the case or suffer a fate from which even you cannot be saved. Soon after, an encounter in a Limehouse opium den proves Mycroft's point.

Conan Doyle specialised in these kind of ghastly forebodings, conveying the creeping pallor of Victorian street life; the fume-filled taverns where a man might find himself propositioned by a burglarising gargoyle; the Thameside staircases where gimlet-eyed doxies awaited the easily duped. Even his cheerful scenes felt vaguely gruesome. Shopkeepers would drape a Christmas goose around a character's neck like a feather boa, and the welcoming yellow light of a first-floor window could somehow suggest that its tenant was lying dead on the floor. The Holmes adventures were virtually horror stories. Men went raving mad in locked rooms, or died of fright for no discernable reason. Women were simply unknowable.

Horowitz proves pitch-perfect in atmosphere and dialogue. Fog muffles murderers' footsteps; London sunlight is always watery; an exchange between the Holmes brothers delights; Lestrade proves pleasingly helpful. The novel works as a tribute and a grace note, but also as a politically damning Victorian shocker with a cast-iron conundrum at its heart.

If there's a complaint, it's that the "official" tag requires strict adherence to canonical rules. For a less respectful, joyously freewheeling take on Holmes, you should catch Kim Newman's superbly witty new Moriarty novel, The Hound of the D'Urbervilles.

Christopher Fowler's latest novel, Bryant & May and the Memory of Blood, is published by Doubleday