Tom Girton was a resident of the town of Devil's End and a regular at the Cloven Hoof. Along with landlord Bert Walker and several other townspeople, Tom was a member of the witches' coven run by the vicar "Reverend Magister," in reality the Doctor's arch-enemy the Master. He informed the Master of the Doctor's arrival shortly before Professor Horner opened the Devil's Hump, and participated in the ritual that helped free Azal from within the barrow.
After Azal used his power to trap Devil's End inside of a heat shield, the Master instructed Tom to kill the Doctor. Tom overpowered Mike Yates and stole a UNIT helicopter for this purpose. He pursued the Doctor and Jo Grant, who fled from him in Bessie. Tom made repeated attempts to strafe them, and the chase led to the edge of town, where Tom overshot his intended target and flew straight into the heat shield. The helicopter exploded on contact with the invisible barrier, killing him.