Duncan was anMI6 agent in the21st century. He was a close ally ofGrace Holloway and later, theEighth Doctor.

Duncan assisted Grace in her experiments onhumans andTime Lords. He arrested the Doctor andIzzy Sinclair until he realised the Doctor was a Time Lord and a close friend of Grace's. He was killed bythe Master whilst trying to stopDonald Stark. (COMIC:The Fallen)