The film, which was directed by Claude Whatham and produced by Richard Pilbrow, starred Virginia McKenna and Ronald Fraser, with Zanna Hamilton.

As part of their strategy the Walkers make a dangerous crossing of the lake by night, and John is later cautioned by his mother for this reckless act.

The Walkers nevertheless win the contest – thanks to Titty who seizes the Amazon when the Blacketts come to Wild Cat Island.

Eventually there is a mock battle between "Captain Flint" and the children, after which Uncle Jim is tried for his crimes and forced to walk the plank on his own houseboat.

In April 2010, the dinghy named Swallow in the film was bought by a group of enthusiasts who restored her to sailing condition.