|Place of origin:||Earth|
TV: The Sound of Drums
PROSE: The Story of Martha
|Main actor:||Elize du Toit|
- For other individuals named Dexter, see Dexter Townsend.
Miss Dexter was a ruthless security agent working for Mr Saxon, entrusted with the task of finding the Tenth Doctor and his companions. Miss Dexter enlisted Francine Jones's help, tapping and tracing Francine's phone conversations with her daughter Martha, who was travelling with the Doctor at this time. (TV: 42)
- No clear indications exist that Miss Dexter was aware of "Saxon"'s true identity or of the extraterrestrial origins of either him or the Doctor.