Bailey was a trooper under Lieutenant Scott who ventured into a cave system to investigate the disappearance of seven members of Professor Kyle's archaeological expedition in 2526.
After Walters lost contact with Baines, Collis and Snyder, Sergeant Mitchell took Bailey and Carter to investigate.
After Carter found Snyder's remains, two Cyberman androids ambushed them, killing Bailey, Carter and Mitchell. (TV: Earthshock)