Louise Bamford

 was a time traveller. Multiple versions of her existed due to this.

The original Louise Bamford was born in 1975 in a timeline where WOTAN had been partly successful in 1969. By 2006 she had become a colonel. Time travel experiments were being done by then, and she was one of the subjects, sent back to 1972. With her knowledge she gained power, eventually becoming a general and exerting great control in England. She married in 2001 and had no children.

However, due to the changes her actions had caused, England was on the verge of being invaded. She told the First Doctor when she had arrived originally, so that he and his companions could go back using the experimental equipment, recover the TARDIS and correct the timeline.

Their presence in 1972, unfortunately, led to Bamford's mother Karen Baldwin being killed. Therefore when Bamford arrived, she existed in a timeline in which she had never been born. They recovered the TARDIS and fixed history as much as possible.

The Doctor, later in his own timeline, completely stopped WOTAN before it could carry out its plans. What effects this had on Bamford were unknown. (PROSE: The Time Travellers)