| Cast list | | Ralph Richardson | as | Prof. Heatherville | | Raymond Huntley | as | Prof. Laxton-Jones | | John Laurie | as | Dr. McVitie | | Ernest Jay | as | Dr. Dainty | | David Tomlinson | as | Mr. Watlington | | Finlay Currie | as | Sir Duncan Wills | | Norman Webb | as | Dr. Wainwright | | Michael Hordern | as | Lt. Cmdr. Lowther | | Pamela Matthews | as | Mrs. Watlington | | Joan Haythorne | as | Mrs. Laxton-Jones | | Joan Young | as | Mrs. McVitie | | Ann Wilton | as | Mrs. Dainty | | Richard Attenborough | as | Jack Arnold | | David Hutcheson | as | Squadron Leader Sowerby | | Patrick Waddington | as | Group Capt. Aspinall |
| | Crew list: | | Peter Ustinov (Director) | | Peter Ustinov (Writer) |
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