Bigon

Bigon was originally a Greek philosopher. He and other Greeks were abducted by Monarch on his fourth visit to Earth and converted into androids.

Biography
Bigon was promised he would rule over Europe once the planet had been conquered, but he rejected this offer, as he believed democracy was the best form of government. Monarch kept him to provide an element of doubt in his perfect society; he believed it was an intellectual galvaniser.

Bigon helped the Fifth Doctor defeat Monarch. Although the Doctor offered to return Bigon, Kurkutji, Lin Futu, Villagra and their respective peoples to their proper time zones on Earth, Bigon told him they would no longer have any place there; they would instead travel on to find another planet on which to settle. (TV: Four to Doomsday)