Sherlock is one of the most intelligent and compelling TV shows we’ve ever watched so it’s surprising that they would make any blunder at all, let alone one so obvious.

Eagle-eyed fans on Twitter outsmarted the show when they noticed something amiss with John Watson’s blog. Sherlock’s sidekick is well known for documenting the duo’s adventures online but as one fan pointed out, his blog is entirely non-existent. With a perfectly times screenshot, the fan pointed out that Martin Freeman is simply looking at a picture file labelled JOHN BLOG PAGE.jpg. It’s a simple mistake but one that Sherlock himself would have noticed in a heartbeat. https://twitter.com/caslxcked/status/815701993545080832 Elsewhere, the return of the detective drama inspired a surge in Google searches for the word “Ammo.” During the show it was used by Sherlock's captors as a code word as they whispered among themselves. "Ammo", was used for the codename of a British woman. The first thing people did when they heard it was Google the term leading to a huge spike on Google trends. Twitter user, Cormac O'Malley, spotted the trend. https://twitter.com/cormacpro/status/815727891128483840 Sherlock's much anticipated return pulled in an incredible 8.1 million viewers. The new season will be delivered in weekly installments with “The Lying Detective” arriving on the 8th January and the finale, “The Final Problem,” on the 15th.