Eleanor (Golden Age)

Eleanor, often simply referred to as The Duchess, was the leader of Torchwood India and a former lover of Captain Jack Harkness. After Torchwood India was shut down by Jack, she froze the base in time, effectively giving herself and her friends immortality. After one hundred extra years of life, she had effectively gone insane. She planned to send the Earth back to her time to remake the world to her liking. After Jack stopped her plan, she elected to stay in the base, and was frozen in time forever. (BBCR: Golden Age)

Behind the scenes
Polly Wright companion of the Second Doctor was also refered to as Duchess.