Episode 5Series Episode Number: 190
World Premiere: Sat 20 Jan 1968 - 5:24pm GMT [BBC One] (United Kingdom)
Running Time: 24 minutes 22 seconds
6.90 Million (UK)Appreciation Index: 49 (UK)
Chart Position: 73 () (UK)
Recorded on Sat 30 Dec 1967 in Lime Grove D
Archive State: Found (11-Oct-13)
Impersonating Salamander, the Doctor infiltrates the research centre, but Benik becomes suspicious. Underground, Salamander's deception is discovered.