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Tom Baker
The Doctor

Elisabeth Sladen
Sarah Jane Smith

Ian Marter
Harry Sullivan

Nicholas Courtney
Brigadier Lethbridge-Stewart

John Levene
RSM Benton

John Woodnutt
Duke of Forgill / Broton

Keith Ashley
Zygon

Ronald Gough
Zygon

Lillias Walker
Sister Lamont

Angus Lennie
Angus

Tony Sibbald
Huckle

Hugh Martin
Munro

Robert Russell
The Caber