Anthony Eustrel as Harry Domain

Eugene Leahy as Dr. Gall

Derek Tansley as Dr. Hellman

Maurice Bannister as Jacob Berman

John Stuart as Alquist

Evelyn Moore as Emma

Joy Adamson as Sulla, a robotess

Patrick Troughton as Radius, a robot

Dermot Palmer as Primus, a robot

Viola Merrett as Helena, a robotess

John Baker as Marius, a robot

Pamela Stirling as Helena Glory