 Gatiss says that they wanted to " fetishise modern London in the way that the period versions fetishise Victorian London " . Production was based at Hartswood Films ' Cardiff production unit , Hartswood Films West , which was opened in late 2009 to take advantage of the BBC 's planned Cardiff Bay " drama village " . Production of the first two series was based at Upper Boat Studios , where Doctor Who had been produced . Cardiff was more economical than in London , with some good matches for parts of London . Some architecture could not be faked , so location shooting in the English capital was necessary . The location shots for 221B Baker Street were filmed at 187 North Gower Street – Baker Street was impractical because of heavy traffic , and the number of things labelled " Sherlock Holmes " , which would need to be disguised . Executive producer Beryl Vertue explains how it was important to design the entirety of Sherlock 's flat as a contemporary set , yet still convey his eccentricity . He would not , she says , live somewhere " too suburban " or " too modern " . 
