A bit of a sneaky one this, as Paul Chequer never actually appeared in Doctor Who, rather its spin-off Torchwood. However, the shows are set in the same world so it would be remiss for us not to include him here. In 2006 episode Random Shoes, Chequer plays the unfortunate Eugene Jones, a man who encounters the Torchwood team after a bizarre turn in his life. Chequer later appeared in the Sherlock episode The Blind Banker as the ill-tempered DI Dimmock. Only its second story, the makers were at this point intending for Sherlock to work with a different detective on each case however due to the popularity of Rupert Graves' Lestrade this strategy was not pursued after this episode.
