Why Every Modern Companion Left Doctor Who

Billie Piper's Rose was a tough act to follow, and Freema Agyeman had her work cut out for her when Martha Jones succeeded Rose Tyler in the TARDIS. Eventually becoming tired of being treated like second best, Martha left the TARDIS to look after her traumatised family after they spent a year imprisoned by the Master.

Given that Martha's story is quite self-contained, it's widely assumed that Freema was contracted for a one season storyline, which was why she left the show at the end of The Last of the Time Lords. Martha then became a recurring character, crossing over into Torchwood and appearing in five out the thirteen episodes of season 4.

Interestingly, Freema Agyeman recently confirmed the original plan was for Martha to become a Torchwood regular following her final TARDIS departure in Journey's End, but delays with scripts and contracts ultimately led to the plan being scrapped. Instead, Freema signed on for Chris Chibnall's Law and Order UK alongside past and future Doctor Who stars, Peter Davison and Bradley Walsh.