The Headmaster and governors of a boarding school are accidentally locked in the new memorial room with the convicted Great Train Robbers.
| Actor | Role |
|---|---|
 Richard PearsonHeadmaster | Headmaster |
 John Le MesurierCanon Dunwoodie | Canon Dunwoodie |
 Barbara CouperMrs Craxton-Christie | Mrs Craxton-Christie |
| JJane EcclesMiss Plimsoll | Miss Plimsoll |
 Stanley MeadowsLionel Smeed | Lionel Smeed |
 Priscilla MorganBeryl Smeed | Beryl Smeed |
 David HutchesonMajor Craxton-Christie | Major Craxton-Christie |
| DDonald EcclesAlfred Remnant | Alfred Remnant |
 Michael BatesMike MacFarland | Mike MacFarland |