Dennis Palmer
Corporal Palmer was a UNIT soldier who served under Brigadier Lethbridge-Stewart. He was seconded to UNIT during the Master's attempt to take control of Kronos using TOMTIT (TV: The Time Monster, PROSE: The Shadow in the Glass).
He defended UNIT HQ from Omega's Gell guards. He witnessed the disappearance of UNIT HQ. (TV: The Three Doctors)
By 2001, he had been promoted to Colonel and was a prominent figure in UNIT's UK branch. He asked for the Brigadier's insight into strange imps surrounding the village of Turelhampton, resulting in the Brigadier and the Sixth Doctor exposing a branch of the Fourth Reich led by Adolf Hitler's son (PROSE: The Shadow in the Glass).