10 things you didn't know about Sherlock Holmes

3: Intravenously, my dear Watson

When not cracking crimes, Holmes liked to while away the hours shooting up cocaine and morphine.

Dr Watson had an inkling that the detective was a drug user shortly after they first met, when he noticed Holmes had a habit of lying around on his sofa for hours on end with a "dreamy, vacant expression in his eyes". His suspicions were soon confirmed when Holmes began injecting drugs right in front of him, his arm "dotted and scarred with innumerable puncture-marks." Holmes even suggested Watson try some, but the good doctor wisely turned down the offer.

4: Not so elementary

Contrary to popular belief, the Holmes of Conan Doyle's stories never actually said "Elementary, my dear Watson".

This immortal catchphrase was actually popularised in TV and film versions of the works. For a long time it was generally thought the line was first uttered in a 1929 Sherlock Holmes movie, but evidence now suggests it was probably coined decades before in a Victorian stage adaptation of the original stories.