Tom Baker

The Doctor

Elisabeth Sladen

Sarah Jane Smith

Tony Beckley

Harrison Chase

Kenneth Gilbert

Richard Dunbar

Michael Barrington

Sir Colin Thackeray

Sylvia Coleridge

Amelia Ducat

John Challis

Scorby

Mark Jones

Arnold Keeler / Krynoid (voice)

Seymour Green

Hargreaves

Michael McStay

Derek Moberley

Hubert Rees

John Stevensen

John Gleeson

Charles Winlett

Ian Fairbairn

Doctor Chester

John Acheson

Major Beresford

Ray Barron

Sergeant Henderson

Alan Chuntz

Chauffeur

David Masterman

Guard Leader

Harry Fielder

Guard

Pat Gorman

Guard

Ian Elliott

Guard

Keith Ashley

Sir Colin's Aide

Ronald Gough

Marine

Patrick Milner

Marine

Barry Summerford

UNIT Soldier

Tony Snell

UNIT Soldier

Patrick Ginter

UNIT Soldier

Rowland Geall

UNIT Soldier

Derek Wayland

UNIT Soldier

Keith Ashley

The Krynoid

Ronald Gough

The Krynoid