 After the high ratings for " A Study in Pink " , the BBC were reportedly eager to produce more episodes . On 10 August 2010 , it was confirmed that Sherlock had been renewed for a second series . At the 2011 convention , Gatiss confirmed which stories would be adapted , and that the writers of the first series would each write an episode for series two . Acknowledging that " A Scandal in Bohemia " , " The Hound of the Baskervilles " and " The Final Problem " are amongst the best @-@ known Holmes stories , Gatiss explained , " We knew after having a successful first run that the natural order would be to do three of the most famous [ stories ] . " " There 's the question of how to go out on a cliffhanger and then the thematic things of the three stories , where we were trying to get to and what Sherlock and John 's relationship is a little further on . You can 't just go back to : ' You have no emotions . ' ' I don 't care . ' You 've got to move on somewhere and make sure the other characters have something of a journey too . " Paul McGuigan directed the first two episodes , and Doctor Who director Toby Haynes handled the last one . The second series of three 90 @-@ minute episodes was initially planned to air in late 2011 , but was delayed until early January 2012 . 
