Last updated 24 March 2024


Part Six

Series 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?


Characters hide uncredited
Doctor WhoTom Baker
Sarah Jane SmithElisabeth Sladen
Harry SullivanIan Marter
DavrosMichael Wisher
NyderPeter Miles
GharmanDennis Chinnery
SevrinStephen Yardley
BettanHarriet Philpin
KravosAndrew Johns
Thal SoldierJohn Gleeson
Dalek OperatorJohn Scott Martin
Dalek OperatorCy Town
Dalek OperatorKeith Ashley
Dalek VoiceRoy Skelton
Scientist (Kalid)Harry Van Engel (uncredited)
Scientist (Kalid)John Timberlake (uncredited)
Scientist (Kalid)William Ashley (uncredited)
Scientist (Kalid)Alan Charles Thomas (uncredited)
Scientist (Kalid)Pat Travis (uncredited)
Scientist (Kalid)Charles Rayford (uncredited)
Scientist (Kalid)Mike Raynell (uncredited)
Scientist (Kalid)Tony Hayes (uncredited)
Guard (Elite)Barry Summerford (uncredited)
Guard (Elite)Roy Caesar (uncredited)
Soldier (Thal)David Billa (uncredited)
SoldierTim Blackstone (uncredited)
Guard (Thal)Reg Turner (uncredited)