The inspiration for Willy Wonka's infamous Inventing Room, with its burbling machines and Everlasting Gobstoppers came from an unlikely source: school.

Roald Dahl went to a famous English public school called Repton, where he boarded along with lots of other young boys. He talks about his schooldays in his first set of autobiographical stories, Boy: Tales of Childhood.

In Boy he tells us that it was whilst at Repton that the idea for Charlie and the Chocolate Factory was sown. This is because he and his classmates were the very willing guinea pigs of the famous chocolate-making company, Cadburys.

Each year, Roald and his friends would be sent a number of Cadbury's newest chocolate inventions to test out. They would arrive in plain packaging, but they were always full of delicious chocolate treats and the boys were invited to share their thoughts on each and every one.

This experience made Roald think about the great chocolate-making companies and the incredible factories they must use to invent their confectionary creations.

The images above show extracts of a speech Roald gave where he talks about how this experience helped to inspire Charlie and the Chocolate Factory. You can see how his time as a schoolboy chocolate-tester stayed with him right through to adulthood.