6. A detective and a doctor walked into a bar…

Having said that, we do know that one scene in particular was actually cut from The Sign of Three. In the John’s stag night sequence, the drunken duo would have ended up at a gay bar. Presumably by mistake, as Sherlock was to have asked John why no one was wearing any shirts.

7. Magnussen’s Accent

When speaking English, Danish-born Lars Mikkelsen’s natural accent has a strong cockney twang, which he had apparently picked up when he taught himself English by watching British telly. For Magnussen, however, he was instructed to re-find his inner Scandinavian.

8. Is there a future for Sherlock and Janine?

There was an exchange in the original His Last Vow script in which Sherlock and Janine agreed that, if they are not with anyone at aged sixty, they will get together. However, it was cut as it was thought it let Sherlock off the hook for treating Janine so terribly.

9. Mr Holmes’ bowtie

The garish bowtie that Sherlock and Mycroft’s dad wears in the Christmas scene in Vow was an addition by actor Timothy (Benedict’s real-life father) Carlton himself. He always wears such a tie at Christmas to embarrass his son.

10. A killer climax

For the climax of the series, Benedict wanted Sherlock to kill Magnussen in a more vicious way – by breaking his neck – but this was overruled by the producers. “He’d gone a bit Khan,” Steven Moffat later joked, referencing Benedict’s role as the psychotic villain from Star Trek Into Darkness.

Is there a fascinating behind-the-scenes fact from Series Three that we have missed? Leave it in the comments!