Last updated 24 March 2024

Episode One

Series Episode Number: 283

World Premiere: Sat 30 Jan 1971 - 5:15pm BST [BBC One] (United Kingdom)
First Broadcast: Fri 7 Nov 1975 - 6:30pm CST [WTTW 11 Chicago]
Running Time: 24 minutes 39 seconds

6.10 Million (UK)

Chart Position: 61 () (UK)

Recorded on Sat 21 Nov 1970 in Television Centre 3
Archive State: 16mm t/r

At Stangmoor Prison, the Doctor and Jo watch a demonstration of the Keller Machine which can extract evil impulses from criminals. But the experiment goes wrong and a man dies.