Jon Pertwee

The Doctor

Caroline John

Liz Shaw

Nicholas Courtney

Brigadier Lethbridge-Stewart

Ronald Allen

Ralph Cornish

John Abineri

Carrington

Robert Cawdron

Taltalian

Michael Wisher

John Wakefield

Cheryl Molineaux

Miss Rutherford

Ray Armstrong

Grey

Robert Robertson

Collinson

Ric Felgate

Van Lyden / Alien Ambassador

Dallas Cavell

Quinlan

Bernard Martin

Control Room Assistant

John Moreno

Dobson

James Haswell

Corporal Champion

Derek Ware

UNIT Sergeant

William Dysart

Reegan

Cyril Shaps

Lennox

Gordon Sterne

Heldorf

Steve Peters

Alien Ambassador / Lefee

Neville Simons

Alien Ambassador / Michaels

Max Faulkner

UNIT Soldier

John Lord

Masters

Tony Harwood

Flynn

John Levene

Sergeant Benton

James Clayton

Private Parker

Joanna Ross

Control Room Assistant

Carl Conway

Control Room Assistant

Roy Scammell

Technician

Peter Noel Cook

Alien Space Captain

Peter Halliday

Aliens' Voices

Geoffrey Beevers

Private Johnson