Mark Gatiss and his love for the movie, The Private Life of Sherlock Holmes: http://prettyarbitrary.tumblr.com/post/72668347427/mark-gatiss-and-the-private-life-of-sherlock-holmes
And the additional spoiiery thought:
If you think that Mary is a bad guy or a plant by CAM, then the season so far makes a truly dead-on parallel for the movie’s plot—only with John in Sherlock’s place and Mary taking the place of Irene.