An apartment handyman is unusually attached to a pair of boilers he names "Mavis" and "Ethel."
| Actor | Role |
|---|---|
 Richard HearneMr. Pastry | Mr. Pastry |
 William HartnellBert | Bert |
 Austin TrevorSir Hervey Shaw | Sir Hervey Shaw |
 Joan MarionAngela Shaw | Angela Shaw |
| RRobert MoretonJevons | Jevons |
 Ralph TrumanInspector Bridger | Inspector Bridger |
 Ronald AdamPsychiatrist | Psychiatrist |
 Junia CrawfordDiana Little | Diana Little |
 Tony QuinnCracknell | Cracknell |
| SSylvia BidmeadSwissair Girl | Swissair Girl |
 Brian HarringtonPolice Doctor | Police Doctor |
| YYvonne HearneMatron | Matron |
 William MervynRoberts (MI5) | Roberts (MI5) |
| CCyril RenisonPlain Clothes Officer | Plain Clothes Officer |
 Neil WilsonMilligan | Milligan |
 John StuartDoctor | Doctor |