Weve scoured the scenes of Sherlock special, The Abominable Bride, to dig out its nerdy details.

Warning: contains spoilers forThe Abominable Bride.

is the first hint-in-hindsight that whats to follow involves narcotics.

A poster advertising The London Fair can be seen behind Watson and Stamford.

8.When Watson tells Mrs Hudson Blame it on the illustrator, hes out of control.

Paget is thought to have based his illustrations of Sherlock Holmes on his younger brother, Walter.

An ear trumpet stands in for the headphones usually adorning the bison skull.

Arwels (Jones, set designer) little joke, explained Mark Gatiss on a February 2015 set tour.

In the modernSherlock, the pipe tobacco has turned into cigarettes, but here its in the original form.

16.The black dress Mary is wearing here is made from a highly fragile original Victorian fabric.

22.The song Emilia Ricoletti sings a snatch of before her shotgun wedding is Victorian balladThe Maid Of The Mill.

23.Sherlocks exasperated Its never twins!

In that instance (spoiler alert) itwastwins.

24.Sherlock may protest that he never says features of interest, but Watsons right, he really does.

(Also at least once inSherlockseries three,The Sign Of Three).

If you remember,SherlocksThe Great Gamerejigged the idea, updating the orange pips to five telephone pips.

Seeing as this Reichenbach Fall scene is all in Sherlocks mind, the phrase gets a knowing airing here.

(His words, not ours.)

29.Arwel Jones and his set design team built the episodes train carriage interior to recreate this original Paget illustration.

30.The Carmichaels house is actually Tyntesfield House, aNational Trust Propertyat Wraxall near Bristol.

One of the houses rooms also stood in for the Watson dining room for Johns breakfast scene.

32.Theres an elephant in the room.

Theres always an elephant in the room.

Catherine McCormacks face, to be specific.

34.Finally, Mycrofts notebook features all manner of interesting scribbles, no doubt designed to get fan-brains deducing.

As for Vernet, the binary, scarlet roll and the rest of it, over to you…