- Author:
- C.P. Snow
- Adapted for television by:
- John Elliot
- Designer:
- Peter Seddon
- Producer:
- Cedric Messina
- Director:
- Raymond Menmuir
- Roger Quaife:
- Patrick Allen
- Sir Lewis Eliot:
- Alec Clunes
- Sir Hector Rose:
- William Mervyn
- Reporter:
- Raymond Hardy
- Caroline Quaife:
- Sarah Lawson
- Hood:
- Morris Perry
- Badge attendant:
- Peter Thompson
- Sir Francis Getliffe:
- Hugh Cross
- Professor Brodzinski:
- Joseph Furst
- Monty Cave:
- Donald Pickering
- Diana Skidmore:
- Helen Christie
- Reggie Collingwood:
- Maurice Hedley
- Lord Lutkin:
- John Tate
- Man in club:
- Gerald Young
- Peer:
- Sidney Gatcum
- Toastmaster:
- Eric Elliott
- Heckler:
- Andrew Lodge
- Ellen Smith:
- Marty Cruickshank
- Trafford:
- Martin Friend
- Speaker:
- Denis Cowles
- Monteith:
- Tenniel Evans
- Pritchard:
- Kenneth Waller
- Whip:
- Michael Guest