The Empress was portrayed by Sarah Parish.
The Racnoss vessel deep within the Earth's core would be discovered by the Torchwood Institute some time prior to the Battle of Canary Wharf in 2007. The vessel sent out a signal to the Empress' Webstar located on the outer fringes of the galaxy and she began plans to develop Huon particles which she could use to re-awaken her children. Using an abandoned Torchwood base beneath the Thames Flood Barrier, the Empress developed her Huon particles with the aid of roboform scavengers she had employed and also acquired the services of H.C. Clements employee Lance Bennett. After brewing liquid Huons, the Empress had Lance secretly poison his colleague/fiancé, Donna Noble.
When the Tenth Doctor discovered the Huon lab beneath the Thames, the Empress revealed herself to him and Donna. Though the two managed to escape, the Empress was able to continue her plan by force-feeding the Huon liquids to Lance, using him as a new "key" to unlock the Secret Heart within the Earth. The Doctor would return to the base and use a roboform remote control to use the roboform bombs from their killer Christmas trees to blow up the pipes within the flood barrier, causing the water from the Thames river to pour in and cascade down the shaft to the centre of the Earth, drowning the newly-awakened Racnoss before they could reach the surface.
The Empress of the Racnoss had remotely commanded her Webstar ship to attack London, but boarded the ship after the Doctor drowned her "children" by draining the Thames. However, the attack had drained the Webstar's Huon energy, leaving it vulnerable. The British Army had sent in tanks and they opened fire on the ship is it hovered low over London. The Webstar, and the Empress, were destroyed by a hail of artillery fire.