Cmdr. Michael Haydon
Kieron Moore
Kim Hamilton
Lois Maxwell
Jimmy Wheeler
Bryan Forbes
Prof. Merrity
Donald Wolfit
Barbara Noble
Thea Gregory
Larry Noble
Jimmy Hanley
"Lefty" Blake
Barry Keegan
Lefty
Barry Keegan
Colonel Galloway
Alan Gifford
Ellen
Shirley Lawrence
Col. Galloway
Alan Gifford
Captain Ross
Donald Gray
Professor Blandford
Walter Hudd
Capt. Ross
Donald Gray
Tony
Peter Neil
Reporter
Ryck Rydon
Reporter
Rick Rydon
Reporter
Ronan O'Casey
Reporter
Robert O'Neill
Reporter
Robert O'Neil
Professor Bechstein
Carl Jaffe
General Barnett
Charles Richardson
Official (uncredited)
John Baker
Simmons the Technician (uncredited)
Trevor Reid
Expert
Alistair Hunter
Technician (uncredited)
Alastair Hunter
Reporter (uncredited)
Paul Beradi
Technician (uncredited)
Bernard Bresslaw
Young Girl (uncredited)
Jane Dore
Reporter (uncredited)
Patrick Halpin
Reporter (uncredited)
Bill Nagy
Jack the Barman
Tony Quinn
Reporter (uncredited)
Terry Randall
Thomas the Watchman (uncredited)
Leonard Sharp
Gatekeeper (uncredited)
Frank Sieman
Reporter (uncredited)
John Wilder
Reporter (uncredited)
Johnny Wyne