The game is Pooh Sticks, originally described by Milne in Winnie-the-Pooh, which was published in 1926. It was inspired by the game he and his son, Christopher (Robin), would play on Posingford Bridge in Ashdown Forest.
The film distils the Blytonesque spirit of adventure and outdoorsy fun... and transfers it to a new world in which all generations are longing to escape electronic devices and AI.
'We absolutely should challenge stereotypes about ageing. Children do build their understanding of the world from these tiny repeated narratives. If old always equals useless or confused then that's going to shape their perception.'
Director Ben Gregor wanted his cast to interact with the fantastical surroundings as much as possible. And so, on their sound stage in Reading, Gadsdon found herself filming in a grove of marshmallow trees, surrounded by giant flying-saucer plants and Haribo strawberry beds. I did eat a few, she confides. The Land of Birthdays was just as fun she was filmed in those scenes in the middle of a giant cake, as rollerskating elves disco-danced by.