We're used to seeing allegations of whitewashing with so many films and TV shows coming out, but this one dates back to 1964.

In an interview with BBC Radio 4's Today programme to coincide with yesterday's Roald Dahl Day, the author's widow Liccy Dahl revealed: "His first Charlie that he wrote about was a little black boy."

Asked why the protagonist in Charlie and the Chocolate Factory's ethnicity was changed, she replied: "I don't know. It's a great pity."

Ronald Dahl's biographer Donald Sturrock, who was also interviewed, was able to provide elucidation.

"I can tell you that it was his agent who thought it was a bad idea, when the book was first published, to have a black hero," he said. "She said people would ask: 'Why?'"

The white Charlie would subsequently be included the famous 1971 and 2005 film adaptations.