Episode SixSeries Episode Number: 225
World Premiere: Sat 7 Dec 1968 - 5:15pm BST [BBC One] (United Kingdom)
Running Time: 23 minutes 20 seconds
6.50 Million (UK)Appreciation Index: 56 (UK)
Chart Position: 72 () (UK)
Recorded on Fri 25 Oct 1968 in Lime Grove D
Archive State: 16mm t/r
Zoe, Jamie and Isobel confront the Cybermen advancing on them from all sides in the sewers beneath London.
The Doctor hurries to devise a protection from the Cybermen's hypnotic signal, as they set their sights on a paralysed London.