The Doctor
Tom Baker
Sarah Jane Smith
Elisabeth Sladen
Huckle
Tony Sibbald
Munro
Hugh Martin
The Caber
Robert Russell
Harry Sullivan
Ian Marter
Brigadier Lethbridge-Stewart
Nicholas Courtney
RSM Benton
John Levene
Duke of Forgill / Broton
John Woodnutt
Zygon
Keith Ashley
Ronald Gough
Sister Lamont
Lillias Walker
Angus
Angus Lennie
Producer
Philip Hinchcliffe
Script Editor
Robert Holmes
Director
Douglas Camfield
Writer
Robert Banks Stewart
Original Music Composer
Geoffrey Burgon