Episode 3Series Episode Number: 155
World Premiere: Sat 25 Mar 1967 - 5:51pm BST [BBC One] (United Kingdom)
Running Time: 23 minutes 24 seconds
8.50 Million (UK)Appreciation Index: 52 (UK)
Chart Position: 45 () (UK)
Recorded on Sat 18 Mar 1967 in Lime Grove D
Archive State: Missing
The Doctor, Jamie and Polly are sent to work in the gas mines whilst Ben struggles to regain control of his mind. Jamie escapes into an old shaft where the Macra are waiting.