Lenny Vosper

Lenny Vosper was an inmate of Stangmoor Prison. He aided Harry Mailer in his unsuccessful escape attempt, then shortly afterwards in taking control of the prison with the help of the Master. He and Charlie were assigned to guard the Third Doctor and Jo Grant, but they escaped. He and Mailer found them in the processing room, but Vosper was then attacked and killed by the Keller Machine. (TV: The Mind of Evil)

Behind the scenes
Don Houghton named the character after his agent, Margery Vosper. (INFO: The Mind of Evil)