Prisoner (The Mind of Evil)

A prisoner was an inmate of Stangmoor prison. When Harry Mailer and the Master led a breakout, he kept guard over the main gate. When Brigadier Lethbridge-Stewart (posing as a lorry driver) asked to go inside to drop food off, the prisoner allowed him, but was then knocked out by a UNIT soldier hiding in the van. (TV: The Mind of Evil)