 John departed in "Inferno" and Katy Manning as Jo Grant, her replacement, appeared in the following serial "Terror of the Autons".Throughout Pertwee's run, Nicholas Courtney, Richard Franklin and John Levene made regular appearances as The Brigadier, Mike Yates and Sergeant Benton respectively.Katy Manning stepped down from the role of Jo Grant at the end of the tenth season in "The Green Death".