|29 credits in
(this image appears for illustrative purposes only and no attempt is made to supersede any copyright attributed to it)
Hartman oversaw the projects that included the investigation of the Void Ship, as well as the ghost shift experiments that resulted in the invasion by the Cybermen from an alternate universe. She was not personally hostile to the Doctor, yet she was confident in the righteousness of Torchwood's actions to the point of fault, ignoring his recommendations and warnings. Hartman was fiercely patriotic, and believed that Torchwood's work was vital to the survival of the "British Empire" and was certain that their work would in fact lead to the restoration of the United Kingdom to the status of world power. Only when the end was near did she attempt to stop the experiments, only to find that the Cybermen had already taken control over key members of her staff. The controlled staff proceeded to override her orders and allow the Cybermen to continue their invasion.
Yvonne, along with Jackie Tyler, was taken to be upgraded. Yvonne stated that she did her duty for queen and country, and walked into the Cyber-conversion unit, where she was then painfully upgraded.However, Yvonne somehow managed to gain control over her new metallic body and performed one last known service, fending off the Cybermen approaching the top offices long enough for the Tenth Doctor and Rose Tyler to seal the breach between worlds. While fighting against the Cybermen she continued to utter the phrase — "I did my duty for queen and country." while weeping oily tears out her left eye socket. Her actions bought the Doctor and Rose the time they needed to banish the Daleks and Cybermen to the Void.