Part SixSeries Episode Number: 397
World Premiere: Sat 12 Apr 1975 - 5:31pm BST [BBC One] (United Kingdom)
First Broadcast: Tue 18 Mar 1980 - 5:30pm CST [WTTW 11 Chicago]
Running Time: 23 minutes 30 seconds
9.10 Million (UK)Appreciation Index: 56 (UK)
Chart Position: 26 () (UK)
Recorded on Tue 25 Feb 1975 in TC6
The Kaled scientific elite move to prevent the development of the Daleks while the Doctor prepares to destroy his old enemies forever. But is it already too late?