- Author:
- Lyon Todd
- Adapter:
- Alistair Bell
- Costumes supervised by:
- Joyce Hawkins
- Make-up supervised by:
- Gwen Arthy
- Designer:
- Michael Edwards
- Script editor:
- Betty Willingale
- Producer:
- Campbell Logan
- Director:
- Julia Smith
- Alexander Graham Bell:
- Alec McCowen
- Thomas Watson:
- Clive Endersby
- Mabel Hubbard:
- Francesca Annis
- Jonas:
- Andre Dakar
- Mrs. Hubbard:
- Mary Barclay
- Mr. Hubbard:
- John Woodnutt
- Professor Bell:
- John Phillips
- Mrs. Bell:
- Barbara Cavan
- Jeannie:
- Jean Anderson
- Dunlop:
- Don Smith
- Ballachey:
- Hal Galili
- Dr. Ferguson:
- Larry Cross
- Reporter:
- James Balfour
- Griffin:
- Ian Dyson
- Mr. Sanders:
- Peter Carlisle
- A watchman:
- Blake Butler
- Lord Provost:
- James Urquhart