Mysterious man (The Lazarus Experiment)
From Tardis Wiki, the free Doctor Who reference
A mysterious man was an employee of "Harold Saxon" who attended Richard Lazarus' experiment to make himself younger. He planted seeds of doubt in Francine Jones' mind that she should not trust the Tenth Doctor being responsible for Martha Jones' safety. (TV: The Lazarus Experiment [+]Loading...["The Lazarus Experiment (TV story)"]) This led to Francine's decision to let another one of Saxon's agents track the Doctor's whereabouts. (TV: 42 [+]Loading...["42 (TV story)"])
Behind the scenes
According to the scripts for 42 [+]Loading...["42 (TV story)"] and The Sound of Drums [+]Loading...["The Sound of Drums (TV story)"], the mysterious man was originally intended to return and take the role that would instead go to a "sinister woman".[1][2]
