Harriet Derbyshire

Harriet Derbyshire (c.1893-1919) worked for Torchwood's branch in Cardiff in 1918.

Unusually for her time, she had a degree in physics from the University of Oxford (Torchwood website). Alongside Gerald Carter, her colleague from Torchwood, she investigated "hauntings" from the future at St. Tello's Military Hospital in Cardiff. She both escorted Tommy Brockless out of his ward to ensure his cryogenic freezing and returned the "future" Tommy back to his native time so as to ensure that history would take its proper course. She died one year later at the age of 26 while in active serivce. (TW: To the Last Man)

Behind the Scenes
Unintentionally or otherwise, Harriet Derbyshire has the same last name as Delia Derbyshire, the electronic music pioneer associated with Doctor Who.