Second Doctor

The Second Doctor was an incarnation of the Unbound Doctor.

During his travels, he had twice met the Brigadier in the 20th century, aiding him against the Robot Yeti in one of their meetings. The Doctor was eventually detained and tried by the Time Lords. As punishment for violating the non-interference policy, the Doctor was forced to regenerate and was exiled to Earth in the 1970s, though his successor would only arrive in 1997. (AUDIO: Sympathy for the Devil)