Captain Mike Yates

Mike Yates worked for the Brigadier in UNIT, and he helped defeat many alien invasions. Having been brainwashed by BOSS, he was given extended leave, and when he returned to UNIT during the dinosaur invasion, when he revealed that he was working for the enemy.He was then granted sick leave and a chance to retire quietly. He retired to a meditation centre to recover from his experiences and while he was there, he alerted the Doctor and Sarah to the Metebelis Spiders who he helped to defeat.

BOSS was the Biomorphic Organisational Systems Supervisor who was the computer for Global Chemicals and it went mad.

Mike Yates was in The Terror of the Autons to The Claws of Axos, The Dæmons, Day of the Daleks: Episodes 1,2, and 4, The Time Monster: Episodes 1 to 4, The Green Death: Episodes 4 to 6, Invasion/Invasion of the Dinosaurs, Planet of Spiders and The Five Doctors (as a "phantom").