• 
  Neal Arden

   Commentator (2 episodes, 1953)
• 
  Peter Bathurst

  Charles Greene
• 
  Ian Colin

  Detective-Inspector Lomax
• 
  Josephine Crombie

   Secretary (2 episodes, 1953)
• 
  Richard Cuthbert

   Chemist (2 episodes, 1953)
• 
  Isabel Dean

   Judith Carroon (6 episodes, 1953)
• 
  John Glen

  Dr. Gordon Briscoe
• 
  Anthony Green

   Boy (2 episodes, 1953)

• 
  Frank Hawkins

   Detective-Sergeant Best (5 episodes, 1953)
• 
  Katie Johnson

   Miss Wilde (3 episodes, 1953)
• 
  Oliver Johnston

  News Editor
• 
  Hugh Kelly

  John Paterson
• 
  John Kidd

   Sir Vernon Dodds (2 episodes, 1953)
• 
  Duncan Lamont

  Victor Carroon
• 
  Dominic Le Foe

   Second Journalist / ... (2 episodes, 1953)

• 
  Eugene Leahy

   Police Inspector (2 episodes, 1953)
• 
  Bernadette Milnes

   Usherette (2 episodes, 1953)
• 
  Christopher Rhodes

  Dr. Ludwig Reichenheim
• 
  Reginald Tate

  Professor Bernard Quatermass
• 
  Tony Van Bridge

   Producer (2 episodes, 1953)
• 
  Philip Vickers

   American Reporter (2 episodes, 1953)
• 
  Moray Watson

  Peter Marsh
• 
  Patrick Westwood

   First Journalist / ... (2 episodes, 1953)
• 
  Paul Whitsun-Jones

  James Fullalove
• 
  Neil Wilson

   Policeman / ... (2 episodes, 1953)
• 
  Lewis Wilson

   Walters (2 episodes, 1953)