After a lock-keeper entrusts his daughter to a canal Casanova, he is shocked to learn that she is pregnant. He then refuses to open his locks - causing barges to pile up in every direction until the guilty party confesses.
| Actor | Role |
|---|---|
 Harry H. CorbettHemel Pike | Hemel Pike |
 Hugh GriffithJoe Turnbull | Joe Turnbull |
 Eric SykesThe Mariner | The Mariner |
 Ronnie BarkerRonnie | Ronnie |
 Julia FosterChristine Turnbull | Christine Turnbull |
 Miriam KarlinNellie Marsh | Nellie Marsh |
 Eric BarkerMr Parkes, the Foreman | Mr Parkes, the Foreman |
 Derek NimmoDr. Scott | Dr. Scott |
 Norman BirdWaterways Supervisor Albert Williams | Waterways Supervisor Albert Williams |
 Richard BriersTomkins | Tomkins |
 Brian WildePoliceman | Policeman |
 George A. CooperOfficial in Office | Official in Office |
| GGrazina FrameGirl in Office | Girl in Office |
 Jo RowbottomCynthia | Cynthia |
| EEdwin AppsGeorge (Barman) | George (Barman) |
| GGodfrey WinnAnnouncer (voice) | Announcer (voice) |
 Patricia HayesOnlooker (uncredited) | Onlooker (uncredited) |
 Michael RobbinsBargee | Bargee |
 Barbara WindsorFactory Girl (uncredited) | Factory Girl (uncredited) |