Episode 4
Series Episode Number: 275World Premiere: Sat 30 May 1970 - 5:15pm BST [BBC One] (United Kingdom)
First Broadcast: Mon 3 Nov 1975 - 6:30pm CST [WTTW 11 Chicago]
Running Time: 24 minutes 57 seconds
6.00 Million (UK)
Appreciation Index: 60 (UK)Chart Position: 54 () (UK)
Recorded on Fri 08 May 1970 in TC3 / TC6
Archive State: RSC conver
In the parallel world, the drilling project is about to penetrate Earth's crust. The Doctor, arrested as a spy, is unable to convince his captors of the danger that faces them.
Home Region: