H is for... Hartman, Yvonne

Yvonne Hartman was the ruthlessly efficient director of Torchwood One, based in London's Docklands. A strange phenomenon had been discovered above the area, so Torchwood had commissioned the building of the Canary Wharf Tower to reach the anomaly and envelope it. The phenomenon was actually a rift in space / time, through which a spherical object appeared. Torchwood discovered that the rift could supply huge amounts of energy which they decided to harness. Each time the rift was opened, however, strange ghostly figures started to appear all over the planet - which everyone assumed to be the spirits of the dead.
Despite her ruthlessness, Hartman liked to think of herself as an enlightened leader, going so far as to memorise the first names of all her staff.
Torchwood had the capture of the Doctor as an on-going priority, as his involvement with Queen Victoria had inadvertently led to the organisations' creation. When he tried to interfere with one of the "ghost shifts", Hartman spotted the TARDIS on a CCTV camera, and realised that he would be coming to the Tower to investigate. She took him prisoner, and asked him to help identify the strange sphere, which was defying all analysis. He told her that it was a Void Ship - designed to survive in the regions between universes. She was adamant that the shifts should continue, as the rift could free Britain from dependence on foreign oil imports, but the Doctor managed to convince her that to do so would break down the barrier between dimensions. An advance party of Cybermen took over the shift operations through converted staff members, allowing all the ghosts to fully materialise as Cybermen.
This coincided with the Void Ship opening to disgorge the Dalek Cult of Skaro.
Hartman was taken to be converted into a Cyberman. Such was her sense of patriotism and loyalty to Torchwood, she resisted mental conditioning and turned on her own new kind, helping destroy a number of Cybermen and giving the Doctor time to prepare his plan to send all the Cybermen and Daleks back in to the Void.

Played by: Tracy-Ann Oberman. Appearances: Army of Ghosts / Doomsday (2006).

• Oberman had just come off a long run of Eastenders, where she had played Chrissie, the second wife of "Dirty Den" Watts (Leslie Grantham). She murdered her husband in the soap's 20th anniversary episode.
• A fan of the series, Oberman has described her appearance in Doctor Who as a career highlight.