Tim Walker: Mixed-up casting has lost the plot

By casting an attractive woman as Watson, CBS has neatly sidestepped one enduring source of Sherlock Holmes-based speculation: the seething homoerotic tension between the detective and his sidekick. In the BBC's hit show Sherlock, for example, Watson is frequently obliged to inform presumptuous strangers that he and Holmes are just good friends. By contrast, Guy Ritchie's macho movie adaptations seem convinced of the duo's flagrant heterosexuality.

The paradigm for any buddy movie pairing, Holmes and Watson have enjoyed a varied relationship over the years, with Watson portrayed as everything from a bumbler (Nigel Bruce, opposite Basil Rathbone's Holmes) to a brawler (Jude Law, in the Ritchie films).

Sir Arthur Conan Doyle's original Dr Watson met his wife, Mary, during The Sign of Four, and moved out of his and Holmes's lodgings at 221B. Presumably bored of this arrangement, Conan Doyle killed off the unfortunate Mrs Watson without explanation, and moved the doctor back into Baker Street.