 Steven Moffat and Mark Gatiss , Sherlock Holmes fans with experience of adapting or using Victorian literature for television , devised the concept of the series . Moffat had previously adapted the Strange Case of Dr Jekyll and Mr Hyde for the 2007 series Jekyll , while Gatiss had written the Dickensian Doctor Who episode " The Unquiet Dead " . Moffat and Gatiss , both Doctor Who writers , discussed plans for a Holmes adaptation during their numerous train journeys to Cardiff where Doctor Who production is based . While they were in Monte Carlo for an awards ceremony , producer Sue Vertue , who is married to Moffat , encouraged Moffat and Gatiss to develop the project themselves before another creative team had the same idea . Moffat and Gatiss invited Stephen Thompson to write for the series in September 2008 . 
