Many foreign tourists come to London believing that 221B Baker Street was once the home of an actual historic character, rather than the location for a fictional superhero.

These camera-clicking simpletons imagine that old Sherlock really did once stalk the foggy streets of the capital, puffing on his over-sized pipe and peering through a giant magnifying glass.

However, Mark Gatiss and Steven Moffat have now seen to it that no-one will ever again mistake Holmes and Watson as real people. These writers' portrayal of Sherlock is about as realistic as Dr Who or Inspector Gadget, and the character is now firmly established as a key part of the BBC's light entertainment and comedy offering, rather than the keystone of television drama it once was.

This first in a trio of new Sherlock stories was not one for the Conan Doyle purists. Our hero's terrifying death plunge from the roof of St Bart's hospital was swiftly overshadowed by wisecracks about Dr. Watson's new moustache and a hilarious guest appearance by TV illusionist Derren Brown.

We then saw Sherlock contemplating a lingering kiss on the lips with Moriarty, before witnessing Dr. Watson loudly announcing to his landlady that he "was not Sherlock's boyfriend!" Watson later introduced his new heterosexual love interest Mary (played by Martin Freeman's real-life love interest Amanda Abbington) and Sherlock's parents popped in for a cuppa (played by Benedict Cumberbatch's real-life parents). I assume that the remainder of the cast were also related to one another in some way or other, making the role of casting director on this production a less than challenging one.

There was a plot of sorts, which involved a terrorist plot to blow up parliament. When Sherlock located the bomb he quickly defused it by throwing a big switch marked "Off", and this enabled the cast to quickly get back to more important things like motorbike chases and slapstick comedy.

In the midst of all this hilarity Dr. Watson managed to get himself trapped inside a Guy Fawkes bonfire and set on fire, and Sherlock rescued him simply by plunging into the flames like Superman and dragging his partner out by the feet. The watching crowd didn't lift a finger to help, and I found myself a little surprised when Sherlock didn't soar into the sky with Watson draped in his arms like Louis Lane.

Freeman's dry charm and Cumberbatch's piercing eyes just about hold it all together. Apparently one of the pupils in Benedict's eyes is permanently dilated, resulting in his rather unique and slightly scary stare. Many mistake this for eyes of different colours (like David Bowie), but such trivia probably has no place in a TV review and should be left to Cumberbatch's optician to fathom out.

There's no doubting Gatiss and Moffat's enthusiasm, but I can't help thinking they've now gone a little over the top. There's a rumour that in the second episode Sherlock will have a sonic screwdriver so that he can wrap things up even more quickly and have time for a quick song and dance number at the end.

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