- You may be looking for the planet Lethe from The Parliament of Rats.
Lethe was the planet on which Davros masqueraded as 'Professor Vaso'. He developed Mechanoids into 'Juggernauts' using organic material cannibalised from human victims. He was unwittingly assisted in the project by Melanie Bush. Lethe initially had an atmosphere which was poisonous to the Daleks, but not Imperial Daleks. It had been a mining colony. (AUDIO: The Juggernauts)
