Anthony Eustrel
— Harry Domain
Eugene Leahy
— Dr. Gall
Derek Tansley
— Dr. Hellman
Maurice Bannister
— Jacob Berman
John Stuart
— Alquist
Evelyn Moore
— Emma
Joy Adamson
— Sulla, a robotess
Patrick Troughton
— Radius, a robot
Dermot Palmer
— Primus, a robot
Viola Merrett
— Helena, a robotess
John Baker
— Marius, a robot
Pamela Stirling
— Helena Glory
David Scase
— A Robot