• 
  Anton Leader

  regizor

• 
  John Briley (I)

  scenarist

• 
  Ian Hendry

  Tom Lewellin
• 
  Alfred Burke

  Colin Webster
• 
  Alan Badel

  Dr. David Neville
• 
  Barbara Ferris

  Susan Eliot
• 
  Ralph Michael

  Defense Minister
• 
  Ian Hendry (I)

  Col Tom Llewellyn

• 
  Patrick Wymark

  Commander
• 
  Bessie Love

  Mrs. Robbins, Mark's Grandmother
• 
  Sheila Allen (III)

  Diana Looran
• 
  Harold Goldblatt

  Harib
• 
  Yoke-Moon Lee

  Mi Ling (as Lee Yoke-Moon)
• 
  André Mikhelson

  Russian official (as Andre Mikhelson)
• 
  Martin Miller

  Prof. Gruber

• 
  Clive Powell

  Paul
• 
  Roberta Rex

  Nina
• 
  Patrick White

  Mr. Davidson