Along with Santa Claus and Mickey Mouse, he is one of the three best-known personalities on the planet. Orson Welles called him "the world's most famous man who never was", though to millions across the globe he was as real as their family doctor. To a surprising number, he still is.
More than 120 years after his first appearance in print, you can recognise him instantly in silhouette: an angular composition of deer- stalker hat, sharp nose and curly pipe. A dizzy-making who's who of film stars has affected that look, with varying degrees of success: alongside the classic incarnations of the great detective by Basil Rathbone, Peter Cushing and Jeremy Brett, audiences have had to suffer the impersonations of Michael Caine, Peter Cook, Larry Hagman, John Cleese, Tom Baker, even Roger Moore.
Everyone, it seems, has had a turn at being Sherlock Holmes. He's appeared on screen more times than any other fictional character, from the silent-movie period to the present day. And boy, is he present in the present. Guy Ritchie's long-awaited film, Sherlock Holmes, is scheduled for release on Boxing Day, and looks set to be a runaway hit. The trailer, showing Robert Downey Jnr (as Holmes), Jude Law (as Dr Watson) and Rachel McAdams (as Irene Adler, Holmes's arch-rival from the story "A Scandal in Bohemia") disporting themselves in boxing rings and boudoirs, dodging explosions and displaying surprising amounts of naked flesh, amazed audiences at showings of Harry Potter and the Half-Blood Prince in cinemas in June, and has been watched by millions on YouTube. Three weeks ago, a rumour circulated that, even before Ritchie's film comes out, a sequel is planned, starring Brad Pitt as Professor Moriarty.
The shamelessly trendy casting takes us some way from the original stories. Downey Jnr is too debauched to play Holmes who – despite his cocaine habit – was always ascetic and asexual; Law is too young, callow and knowing to be the decent, slow-on-the-uptake middle-aged doctor; and McAdams, though she looks perfectly acceptable in a whalebone corset, is too saucy to play the steely adventuress Adler. Pitt, meanwhile, is simply nobody's idea of a Napoleon of crime. But worse is to come. Columbia Pictures has announced that it is preparing a comedy spoof, produced by Judd Apatow, the golden boy of Hollywood comedy, and starring Sasha Baron Cohen as Holmes and Will Ferrell as Watson.
You can hear a collective groan from the world-wide army of Sherlockians at this disrespectful travesty – but of course they themselves have been playing fast and loose with the literal truth for years. Holmes fans are world-class pedants when it comes to arguing whether or not their hero put an illegal bet on a horse in the story "Silver Blaze", but they're far from academic purists. Far from confining themselves to the texts by Sir Arthur Conan Doyle, they start with the premise that the great detective and his sidekick were real people, whose lives can be investigated as though they were historical figures. They choose to believe that Dr John Watson wrote the stories but let his friend and literary agent, Conan Doyle, publish them under his by-line.
There's a two-volume Annotated Sherlock Holmes edited by WS Baring-Gould, published in 1967, full of "Sherlockian" scholarship (which means a melee of theories and conjectures about the great man's "life") and a nine-volume Sherlock Holmes Reference Library by Leslie S Klinger, the world's foremost Holmes scholar. Klinger is also responsible for the handsome, three-volume New Annotated Sherlock Holmes that was published to massive acclaim by Norton, the distinguished American publishing house in 2005. In its 2,000-odd pages, you can read lively discussions on Conan Doyle's (oops, sorry, Watson's) slip-up in "The Blue Carbuncle" where a valuable precious stone is discovered in the crop (the distended gullet) of a goose – but a goose has no crop. You can read learned articles on the probable nature of the guns carried by both Holmes and Watson. They're never specifically described, but Holmes often tells Watson, "Bring your service revolver" when the game is afoot. The madder Sherlockians will dispute the rival claims of the Webley Metro-Police pistol and the Webley Pocket Hammerless model 1889 until the cows come home.
For millions, Sherlock Holmes will never die, but there's little doubt about his birth. All biographers point to the figure of Dr Joseph Bell of the University of Edinburgh Medicine Faculty, whom Conan Doyle encountered when he was a student there in 1876-77. Bell, at 39 a very young professor, was tall, lean, sharp-nosed, hawk-eyed and a whiz at diagnosis; he loved to show off to the medical students his powers of logic and deduction by closely observing his patients.
Bell's special trick was to sit in the amphitheatre where he gave his lectures and have patients brought to him by the outpatients clerk. He would then deduce several likely facts about the victim, leaving the patient (and the students) stunned. Once, he deduced that a patient, on whom he'd never set eyes before, was a non-commissioned officer recently discharged from a Highland Regiment stationed in Barbados.
A decade later, in March 1886, Conan Doyle, was working on a new book after his first novel, The Firm of Girdlestone, had been rejected by two publishers. He was thinking about his old teacher. "I felt now I was capable of something fresher and crisper and more workmanlike," he wrote later. "Gaboriau [Emile Gaboriau, French crime writer and creator of Inspector Lecoq] had rather attracted me by the neat dovetailing of his plots, and [Edgar Allen] Poe's masterful detective, M. Dupin, had from boyhood been one of my heroes. But could I bring an addition of my own? I thought of my old teacher, Joe Bell, of his eagle face, of his curious ways, of his eerie trick of spotting details. If he were a detective he would surely reduce this fascinating but unorganised business to something nearer to an exact science."
Indeed he could – or, at least, could seem to. Holmes entered the world in the detective mystery novel A Study in Scarlet. It took Conan Doyle six weeks to write, was originally called A Tangled Skein, and starred a nervy detective called Sheridan Hope, later Sherringford Holmes. But Conan Doyle had had a schoolfriend at Stonyhurst called Patrick Sherlock, and his mentor, Bell, had employed an assistant called Dr Patrick Heron Watson...
The first encounter between the two fictional legends occurs in Chapter One, when Doctor Watson, in search of someone with whom to share lodgings, is introduced to a tall, thin "student" waving a test tube in a chemistry lab at St Bartholomew's Hospital. Holmes's first words to Watson are: "How are you? You have been in Afghanistan, I perceive." He explains that he has seen that Watson is "a gentleman of the medical type, but with the air of a military man," tanned by exposure to the tropics, inured to hardship and sickness, and wounded. Where could an army doctor have encountered such trouble? "Clearly in Afghanistan."
Russell Miller, Conan Doyle's most recent biographer, is scornful about this reasoning. "Well, not necessarily, my dear Holmes," he writes. "Why not South Africa, where British forces had recently been engaged in the Zulu War? And since when has Afghanistan been in 'the tropics'? And what is 'a gentleman of the medical type'?"
But the multitude of Holmes fans has learned over the years to gloss over many similar moments of duff reasoning, scientific non-facts (like his suggestion that a large head suggests high intelligence), muddled cultural understanding (such as giving Muslim names to the Sikh characters in The Sign of Four) and logical inferences that are merely guesswork. But Holmes's breezy manipulations of visual data to interpret a world of criminality – and then to confront and overcome it by the use of scientific logic – have caught the public's imagination for 121 years, ever since A Study in Scarlet was finally published in July 1888.
The main outlet for the 56 stories at the centre of the Holmes canon was George Newnes's fantastically trendy Strand Magazine, which started life at Christmas 1890: it was a lightweight compendium of feature articles and illustrations. Conan Doyle's editor submitted two stories ("A Scandal in Bohemia" and "The Red-Headed League") to the magazine's literary editor, Greenhough Smith, who greeted them ecstatically. "There was no mistaking the ingenuity of plot, the limpid clearness of style, the perfect art of telling a story," he later gushed. "The very handwriting full of character and clear as print..."
The stories were published in July and August 1891, and were instantly successful. More followed every month until July 1892. Readers queued to buy the magazine on the day each issue was due out. A quarter of a million copies of the collected Adventures of Sherlock Holmes were sold in the first three years. Gradually, the details of life chez Holmes and Watson were painted in: the rooms at 221B Baker Street, the unanswered letters on the mantlepiece impaled by a jack-knife, the tobacco that's kept in the top of a Persian slipper, the cigars in the coal-scuttle; also the cocaine habit (injected, in a 7 per cent solution, by hypodermic syringe,) the mournful violin playing, the wall pock-marked with bullet holes that spell out 'VR' ('Victoria Regina') and the Bradshaw railway timetable.
A second series of 12 stories was commissioned by the Strand at the then-colossal sum of £1,000 each, and published together as The Memoirs of Sherlock Holmes. When in 1893, at the end of the series, Conan Doyle elected to kill off his hero in the story "The Final Problem", by having him wrestle to the death with the dastardly Professor Moriarty at the Reichenbach Falls in Switzerland, there was a public outcry.
"Not since the death of Dickens's Little Nell 52 years earlier," wrote Russell Miller, "had a fictional character's demise unleashed such an outpouring of public grief and outrage ... The Strand lost 20,000 subscribers, and furious letters poured into their offices by the sackload, many abusing Conan Doyle, others pleading with Newnes to deny the report and promise more stories. One lady reader called Conan Doyle "a brute", another allegedly swatted him with her handbag. The Prince of Wales was said to be particularly anguished..."
Ten years later, Doyle was obliged to bring Holmes and Watson back from the dead in the story "The Adventure of the Empty House", published in Strand Magazine in 1903. Three more collections followed: The Return of Sherlock Holmes, His Last Bow and The Casebook of Sherlock Holmes.
But since the death of Arthur Conan Doyle in 1930, Holmes and his faithful companion have been resurrected many times in the movies and on television. Well before his death, movie- makers had come a-calling. A play called Under the Clock was staged in 1893, only five years after A Study in Scarlet. The next year, Charles Rogers' five-act play Sherlock Holmes was first staged. Conan Doyle co-wrote a drama by the same name with William Gillette in 1899. The first "film", entitled Sherlock Holmes Baffled, could be seen in 1900, but was only 49 seconds long. The first proper screen Holmes was Maurice Costello in the 1905 movie Held for a Ransom, based on the novel The Sign of Four. After this, the floodgates opened. More than 100 Sherlock Holmes films were made in the last century, often in batches.
The Norwegian Nordisk Film Co made 13 films, starring Viggo Larsen, between 1908 and 1911. The Franco-British Film Co made eight more, starring George Treville, and the industrious Stoll Picture Productions made 47 films in only three years, starring Eille Norwood and Hubert Willis. They were silent but pretty sophisticated, using colour tinting in some episodes, and were enterprising in spirit. When there were roadworks in Baker Street, exterior filming was shifted to the studio's headquarters in Cricklewood, while economic pressure meant that the climactic scene of Holmes and Moriarty falling to their deaths at the Reichenbach Falls had to be relocated to Cheddar Gorge in Somerset.
The odd thing was that none of these movies was set in the murky Victorian era: they all had contemporary settings, the 1910s and 1920s. And that's how things stayed right through the 1940s, when Basil Rathbone and Nigel Bruce starred as the deducing duo in 14 films made by Fox, then Columbia. Twelve of them were set in wartime, as Holmes and Watson battled again Nazi villains (such as the sneery German propagandist who, like Lord Haw-Haw, invades British airwaves in Sherlock Holmes and the Voice of Terror). It was only in the 1960s that film-makers, and TV producers, began to exploit the potential of the Victorian atmosphere – gaslight, London fog, cobblestones, peelers, urchins, clubs – that Conan Doyle so matchlessly evoked.
But it's a testament to their appeal that Holmes and his friend were made part of the war effort. Holmes is the brilliant, icy-nerved, mercurial, logical, patriotic superman (but one who likes dressing up and running rings round the cops) and Watson his brave, loyal and slightly- dumber-than-the-reader sidekick. "No wonder," wrote John Le Carré, "the pairing of Holmes and Watson has triggered more imitators than any other in literature. Contemporary cop dramas draw on them repeatedly. They are almost single-handedly responsible for the buddy-buddy movie. The modern thriller would have been lost without them."
Conan Doyle's favourite Holmes impersonator was Eille Norwood, who played the great detective on the London stage for 130 performances. At a Stoll Pictures dinner in 1921, Doyle raised a toast to Norwood, who responded with a poem:
"Lies Sherlock Holmes beneath the soil,
His still remains disarmed, destroyed;
But thanks to Stoll and Conan Doyle
He still remains in celluloid."
Little did either man realise how much more was to come.
Sherlock Holmes goes on general release 26 December